2556921 has 8 divisors (see below), whose sum is σ = 3460384. Its totient is φ = 1679040.

The previous prime is 2556913. The next prime is 2556943. The reversal of 2556921 is 1296552.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2556921 - 2³ = 2556913 is a prime.

It is a Duffinian number.

2556921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2556991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6160 + ... + 6561.

It is an arithmetic number, because the mean of its divisors is an integer number (432548).

2^2556921 is an apocalyptic number.

It is an amenable number.

2556921 is a deficient number, since it is larger than the sum of its proper divisors (903463).

2556921 is a wasteful number, since it uses less digits than its factorization.

2556921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12791.

The product of its digits is 5400, while the sum is 30.

The square root of 2556921 is about 1599.0375230119. The cubic root of 2556921 is about 136.7432098158.

The spelling of 2556921 in words is "two million, five hundred fifty-six thousand, nine hundred twenty-one".