2556891 has 12 divisors (see below), whose sum is σ = 3724032. Its totient is φ = 1690416.

The previous prime is 2556877. The next prime is 2556907. The reversal of 2556891 is 1986552.

It is a happy number.

2556891 is a `hidden beast` number, since 2 + 5 + 568 + 91 = 666.

It is not a de Polignac number, because 2556891 - 2¹⁰ = 2555867 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2556821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25 + ... + 2261.

It is an arithmetic number, because the mean of its divisors is an integer number (310336).

2^2556891 is an apocalyptic number.

2556891 is a deficient number, since it is larger than the sum of its proper divisors (1167141).

2556891 is a wasteful number, since it uses less digits than its factorization.

2556891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2370 (or 2367 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 2556891 is about 1599.0281423415. The cubic root of 2556891 is about 136.7426750174.

The spelling of 2556891 in words is "two million, five hundred fifty-six thousand, eight hundred ninety-one".