256633009 has 2 divisors, whose sum is σ = 256633010. Its totient is φ = 256633008.

The previous prime is 256632991. The next prime is 256633051. The reversal of 256633009 is 900336652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 220968225 + 35664784 = 14865^2 + 5972^2 .

It is a cyclic number.

It is not a de Polignac number, because 256633009 - 2⁷ = 256632881 is a prime.

It is not a weakly prime, because it can be changed into another prime (256630009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128316504 + 128316505.

It is an arithmetic number, because the mean of its divisors is an integer number (128316505).

Almost surely, 2^256633009 is an apocalyptic number.

It is an amenable number.

256633009 is a deficient number, since it is larger than the sum of its proper divisors (1).

256633009 is an equidigital number, since it uses as much as digits as its factorization.

256633009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 29160, while the sum is 34.

The square root of 256633009 is about 16019.7693179396. The cubic root of 256633009 is about 635.4833437401.

The spelling of 256633009 in words is "two hundred fifty-six million, six hundred thirty-three thousand, nine".