256431647 has 2 divisors, whose sum is σ = 256431648. Its totient is φ = 256431646.

The previous prime is 256431631. The next prime is 256431653. The reversal of 256431647 is 746134652.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 256431647 - 2⁴ = 256431631 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256431647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256431697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128215823 + 128215824.

It is an arithmetic number, because the mean of its divisors is an integer number (128215824).

Almost surely, 2^256431647 is an apocalyptic number.

256431647 is a deficient number, since it is larger than the sum of its proper divisors (1).

256431647 is an equidigital number, since it uses as much as digits as its factorization.

256431647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 38.

The square root of 256431647 is about 16013.4832875299. The cubic root of 256431647 is about 635.3170937841.

The spelling of 256431647 in words is "two hundred fifty-six million, four hundred thirty-one thousand, six hundred forty-seven".