256064721 has 16 divisors (see below), whose sum is σ = 381544128. Its totient is φ = 151404800.

The previous prime is 256064701. The next prime is 256064797. The reversal of 256064721 is 127460652.

It is not a de Polignac number, because 256064721 - 2⁵ = 256064689 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (256064701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93276 + ... + 95981.

It is an arithmetic number, because the mean of its divisors is an integer number (23846508).

Almost surely, 2^256064721 is an apocalyptic number.

It is an amenable number.

256064721 is a deficient number, since it is larger than the sum of its proper divisors (125479407).

256064721 is a wasteful number, since it uses less digits than its factorization.

256064721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189312.

The product of its (nonzero) digits is 20160, while the sum is 33.

The square root of 256064721 is about 16002.0224034339. The cubic root of 256064721 is about 635.0139257491.

The spelling of 256064721 in words is "two hundred fifty-six million, sixty-four thousand, seven hundred twenty-one".