256626551 has 4 divisors (see below), whose sum is σ = 257149704. Its totient is φ = 256103400.

The previous prime is 256626541. The next prime is 256626593. The reversal of 256626551 is 155626652.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 256626551 - 2¹⁰ = 256625527 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 (256626541) 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, 260840 + ... + 261821.

It is an arithmetic number, because the mean of its divisors is an integer number (64287426).

Almost surely, 2^256626551 is an apocalyptic number.

256626551 is a deficient number, since it is larger than the sum of its proper divisors (523153).

256626551 is an equidigital number, since it uses as much as digits as its factorization.

256626551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523152.

The product of its digits is 108000, while the sum is 38.

The square root of 256626551 is about 16019.5677532198. The cubic root of 256626551 is about 635.4780131893.

The spelling of 256626551 in words is "two hundred fifty-six million, six hundred twenty-six thousand, five hundred fifty-one".