2556521 has 4 divisors (see below), whose sum is σ = 2788944. Its totient is φ = 2324100.

The previous prime is 2556509. The next prime is 2556523. The reversal of 2556521 is 1256552.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2556521 - 2⁶ = 2556457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2556523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116195 + ... + 116216.

It is an arithmetic number, because the mean of its divisors is an integer number (697236).

2^2556521 is an apocalyptic number.

It is an amenable number.

2556521 is a deficient number, since it is larger than the sum of its proper divisors (232423).

2556521 is a wasteful number, since it uses less digits than its factorization.

2556521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232422.

The product of its digits is 3000, while the sum is 26.

The square root of 2556521 is about 1598.9124428811. The cubic root of 2556521 is about 136.7360788256.

It can be divided in two parts, 255 and 6521, that added together give a palindrome (6776).

The spelling of 2556521 in words is "two million, five hundred fifty-six thousand, five hundred twenty-one".