256644791 has 8 divisors (see below), whose sum is σ = 279071520. Its totient is φ = 234601632.

The previous prime is 256644779. The next prime is 256644793. The reversal of 256644791 is 197446652.

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

It is a cyclic number.

It is not a de Polignac number, because 256644791 - 2⁶ = 256644727 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256644793) 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, 94496 + ... + 97173.

It is an arithmetic number, because the mean of its divisors is an integer number (34883940).

Almost surely, 2^256644791 is an apocalyptic number.

256644791 is a deficient number, since it is larger than the sum of its proper divisors (22426729).

256644791 is a wasteful number, since it uses less digits than its factorization.

256644791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191785.

The product of its digits is 362880, while the sum is 44.

The square root of 256644791 is about 16020.1370468545. The cubic root of 256644791 is about 635.4930685870.

The spelling of 256644791 in words is "two hundred fifty-six million, six hundred forty-four thousand, seven hundred ninety-one".