256439947271 has 2 divisors, whose sum is σ = 256439947272. Its totient is φ = 256439947270.

The previous prime is 256439947193. The next prime is 256439947307. The reversal of 256439947271 is 172749934652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 256439947271 - 2²² = 256435752967 is a prime.

It is a super-2 number, since 2×256439947271² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 256439947271.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256439941271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128219973635 + 128219973636.

It is an arithmetic number, because the mean of its divisors is an integer number (128219973636).

Almost surely, 2^256439947271 is an apocalyptic number.

256439947271 is a deficient number, since it is larger than the sum of its proper divisors (1).

256439947271 is an equidigital number, since it uses as much as digits as its factorization.

256439947271 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22861440, while the sum is 59.

The spelling of 256439947271 in words is "two hundred fifty-six billion, four hundred thirty-nine million, nine hundred forty-seven thousand, two hundred seventy-one".