256339969 has 2 divisors, whose sum is σ = 256339970. Its totient is φ = 256339968.

The previous prime is 256339921. The next prime is 256339973. The reversal of 256339969 is 969933652.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 171479025 + 84860944 = 13095^2 + 9212^2 .

It is a cyclic number.

It is not a de Polignac number, because 256339969 - 2¹⁵ = 256307201 is a prime.

It is a super-2 number, since 2×256339969² = 131420359413841922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (256319969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128169984 + 128169985.

It is an arithmetic number, because the mean of its divisors is an integer number (128169985).

Almost surely, 2^256339969 is an apocalyptic number.

It is an amenable number.

256339969 is a deficient number, since it is larger than the sum of its proper divisors (1).

256339969 is an equidigital number, since it uses as much as digits as its factorization.

256339969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2361960, while the sum is 52.

The square root of 256339969 is about 16010.6205064014. The cubic root of 256339969 is about 635.2413730951.

The spelling of 256339969 in words is "two hundred fifty-six million, three hundred thirty-nine thousand, nine hundred sixty-nine".