256570009 has 2 divisors, whose sum is σ = 256570010. Its totient is φ = 256570008.

The previous prime is 256569883. The next prime is 256570021. The reversal of 256570009 is 900075652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 164352400 + 92217609 = 12820^2 + 9603^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256570009 is a prime.

It is not a weakly prime, because it can be changed into another prime (256570049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128285004 + 128285005.

It is an arithmetic number, because the mean of its divisors is an integer number (128285005).

Almost surely, 2^256570009 is an apocalyptic number.

It is an amenable number.

256570009 is a deficient number, since it is larger than the sum of its proper divisors (1).

256570009 is an equidigital number, since it uses as much as digits as its factorization.

256570009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18900, while the sum is 34.

The square root of 256570009 is about 16017.8028767993. The cubic root of 256570009 is about 635.4313385735.

The spelling of 256570009 in words is "two hundred fifty-six million, five hundred seventy thousand, nine".