256375661 has 4 divisors (see below), whose sum is σ = 256751712. Its totient is φ = 255999612.

The previous prime is 256375633. The next prime is 256375697. The reversal of 256375661 is 166573652.

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 256375661 - 2⁶ = 256375597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256375261) 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, 187001 + ... + 188366.

It is an arithmetic number, because the mean of its divisors is an integer number (64187928).

Almost surely, 2^256375661 is an apocalyptic number.

It is an amenable number.

256375661 is a deficient number, since it is larger than the sum of its proper divisors (376051).

256375661 is an equidigital number, since it uses as much as digits as its factorization.

256375661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376050.

The product of its digits is 226800, while the sum is 41.

The square root of 256375661 is about 16011.7351027301. The cubic root of 256375661 is about 635.2708547543.

The spelling of 256375661 in words is "two hundred fifty-six million, three hundred seventy-five thousand, six hundred sixty-one".