256964021 has 4 divisors (see below), whose sum is σ = 257455872. Its totient is φ = 256472172.

The previous prime is 256964017. The next prime is 256964033. The reversal of 256964021 is 120469652.

It is a happy number.

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 256964021 - 2² = 256964017 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 (256964221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245141 + ... + 246186.

It is an arithmetic number, because the mean of its divisors is an integer number (64363968).

Almost surely, 2^256964021 is an apocalyptic number.

It is an amenable number.

256964021 is a deficient number, since it is larger than the sum of its proper divisors (491851).

256964021 is an equidigital number, since it uses as much as digits as its factorization.

256964021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491850.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 256964021 is about 16030.0973484256. The cubic root of 256964021 is about 635.7564473946.

The spelling of 256964021 in words is "two hundred fifty-six million, nine hundred sixty-four thousand, twenty-one".