256440551 has 2 divisors, whose sum is σ = 256440552. Its totient is φ = 256440550.

The previous prime is 256440539. The next prime is 256440623. The reversal of 256440551 is 155044652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256440551 - 2¹⁴ = 256424167 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256442551) 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 as a sum of consecutive naturals, namely, 128220275 + 128220276.

It is an arithmetic number, because the mean of its divisors is an integer number (128220276).

Almost surely, 2^256440551 is an apocalyptic number.

256440551 is a deficient number, since it is larger than the sum of its proper divisors (1).

256440551 is an equidigital number, since it uses as much as digits as its factorization.

256440551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24000, while the sum is 32.

The square root of 256440551 is about 16013.7613008312. The cubic root of 256440551 is about 635.3244470080.

The spelling of 256440551 in words is "two hundred fifty-six million, four hundred forty thousand, five hundred fifty-one".