2556401 has 4 divisors (see below), whose sum is σ = 2559600. Its totient is φ = 2553204.

The previous prime is 2556397. The next prime is 2556403. The reversal of 2556401 is 1046552.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2556401 - 2² = 2556397 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2556403) 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, 770 + ... + 2388.

It is an arithmetic number, because the mean of its divisors is an integer number (639900).

2^2556401 is an apocalyptic number.

It is an amenable number.

2556401 is a deficient number, since it is larger than the sum of its proper divisors (3199).

2556401 is a wasteful number, since it uses less digits than its factorization.

2556401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3198.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 2556401 is about 1598.8749169338. The cubic root of 2556401 is about 136.7339393834.

The spelling of 2556401 in words is "two million, five hundred fifty-six thousand, four hundred one".