256664553 has 4 divisors (see below), whose sum is σ = 342219408. Its totient is φ = 171109700.

The previous prime is 256664543. The next prime is 256664561. The reversal of 256664553 is 355466652.

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 256664553 - 2¹⁷ = 256533481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (256664543) 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, 42777423 + ... + 42777428.

It is an arithmetic number, because the mean of its divisors is an integer number (85554852).

Almost surely, 2^256664553 is an apocalyptic number.

It is an amenable number.

256664553 is a deficient number, since it is larger than the sum of its proper divisors (85554855).

256664553 is an equidigital number, since it uses as much as digits as its factorization.

256664553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85554854.

The product of its digits is 648000, while the sum is 42.

The square root of 256664553 is about 16020.7538212158. The cubic root of 256664553 is about 635.5093794469.

The spelling of 256664553 in words is "two hundred fifty-six million, six hundred sixty-four thousand, five hundred fifty-three".