>>> time.ctime(time.time()); pbkdf2.PBKDF2('000000000000000009b7fb236187f120a0c86eb8785f099a8d197dd34b9d2553', 'pevpot', 5000000000, hashlib.sha256, hmac).hexread(32); time.ctime(time.time())
'Tue Nov 17 01:50:44 2015'
'6e466cdd13cc80b1137addf46362bbe3714fc9bf7faef9aba930554d3e080ba5'
'Tue Nov 17 23:44:24 2015'

>>> time.ctime(time.time()); pbkdf2.PBKDF2('000000000000000009b7fb236187f120a0c86eb8785f099a8d197dd34b9d2553', 'pevpot', 5000000000, hashlib.sha256, hmac).hexread(32); time.ctime(time.time())
'Tue Nov 17 01:50:44 2015'

> parseInt('6e466cdd13cc80b1137addf46362bbe3714fc9bf7faef9aba930554d3e080ba5',16)
4.9878843987532516e+76
> parseInt('6e466cdd13cc80b1137addf46362bbe3714fc9bf7faef9aba930554d3e080ba5',16) == parseInt('6e466cdd13cc80b1137addf46362bbe3714fc9bf7faef9aba930554d3e080ba5',16)+1
true

#include <stdio.h>
#include <string.h>
#include <openssl/hmac.h>
#include <openssl/evp.h>

int pbkdf2(const char *pass, const unsigned char *salt, long iter, const EVP_MD *digest, unsigned char *out)
{
  unsigned char digtmp[32], itmp[4];
  int k, mdlen, saltlen = strlen(salt);
  unsigned long j;
  HMAC_CTX hctx_tpl, hctx;

  mdlen = EVP_MD_size(digest);
  HMAC_CTX_init(&hctx_tpl);
  HMAC_Init_ex(&hctx_tpl, pass, strlen(pass), digest, NULL);
  itmp[0] = itmp[1] = itmp[2] = 0; itmp[3] = 1;
  HMAC_CTX_copy(&hctx, &hctx_tpl); HMAC_Update(&hctx, salt, saltlen); HMAC_Update(&hctx, itmp, 4); HMAC_Final(&hctx, digtmp, NULL); HMAC_CTX_cleanup(&hctx);
  memcpy(out, digtmp, mdlen);
  for (j = 1; j < iter; j++) {
    HMAC_CTX_copy(&hctx, &hctx_tpl); HMAC_Update(&hctx, digtmp, mdlen); HMAC_Final(&hctx, digtmp, NULL); HMAC_CTX_cleanup(&hctx);
    for (k = 0; k < mdlen; k++) out[k] ^= digtmp[k];
    if (j % 10000000 == 9999999) {
      int i;
      printf("%lu ", (j+1)/1000000);
      for (i=0;i<32;i++) printf("%02x", out[i]);
      printf("\n");
    }
  }
  HMAC_CTX_cleanup(&hctx_tpl);
  return 1;
}

void main()
{
    size_t i;
    unsigned char out[32];
    const char pwd[] = "000000000000000009b7fb236187f120a0c86eb8785f099a8d197dd34b9d2553";
    pbkdf2(pwd, "pevpot", 5000000000, EVP_sha256(), out);
    printf("out: "); for(i=0;i<32;i++) { printf("%02x", out[i]); } printf("\n");
}

$ gcc -O3 pbkdf2.c -lssl -lcrypto
$ ./a.out 
pass: 000000000000000009b7fb236187f120a0c86eb8785f099a8d197dd34b9d2553
ITERATION: 5000000000
salt: 706576706f74
10 4e54363ee4f5a8f0a13f36fcbe46568e496c787ac24ab466e18b80f959c4e426
20 1c08cfe17c6b036075fb45ea1d5b95073ebdfdd4a329cd1a30030e34f26cb8b1
30 110a65fb8928595ad797371bf1f77db371d62af560b6431704b7e91157a89065
[...]
4980 522f0ace7099f90c9a358014500f702fb10ab7f3a0ebeb3a7c221be91309a0d8
4990 38ca9ef690e27bcef846ef9852161f8f33223499fc2c57c1f0116995cb09744c
5000 6e466cdd13cc80b1137addf46362bbe3714fc9bf7faef9aba930554d3e080ba5
out: 6e466cdd13cc80b1137addf46362bbe3714fc9bf7faef9aba930554d3e080ba5
$ 

>>> print 0x6e466cdd13cc80b1137addf46362bbe3714fc9bf7faef9aba930554d3e080ba5 % 2370006599
2341821270