256322921 has 4 divisors (see below), whose sum is σ = 256478352. Its totient is φ = 256167492.

The previous prime is 256322917. The next prime is 256322947. The reversal of 256322921 is 129223652.

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 256322921 - 2² = 256322917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256322981) 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, 75215 + ... + 78548.

It is an arithmetic number, because the mean of its divisors is an integer number (64119588).

Almost surely, 2^256322921 is an apocalyptic number.

It is an amenable number.

256322921 is a deficient number, since it is larger than the sum of its proper divisors (155431).

256322921 is a wasteful number, since it uses less digits than its factorization.

256322921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155430.

The product of its digits is 12960, while the sum is 32.

The square root of 256322921 is about 16010.0881009444. The cubic root of 256322921 is about 635.2272904492.

The spelling of 256322921 in words is "two hundred fifty-six million, three hundred twenty-two thousand, nine hundred twenty-one".