256673657 has 2 divisors, whose sum is σ = 256673658. Its totient is φ = 256673656.

The previous prime is 256673611. The next prime is 256673689. The reversal of 256673657 is 756376652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 197936761 + 58736896 = 14069^2 + 7664^2 .

It is a cyclic number.

It is not a de Polignac number, because 256673657 - 2⁸ = 256673401 is a prime.

It is not a weakly prime, because it can be changed into another prime (256673057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128336828 + 128336829.

It is an arithmetic number, because the mean of its divisors is an integer number (128336829).

Almost surely, 2^256673657 is an apocalyptic number.

It is an amenable number.

256673657 is a deficient number, since it is larger than the sum of its proper divisors (1).

256673657 is an equidigital number, since it uses as much as digits as its factorization.

256673657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1587600, while the sum is 47.

The square root of 256673657 is about 16021.0379501454. The cubic root of 256673657 is about 635.5168932867.

The spelling of 256673657 in words is "two hundred fifty-six million, six hundred seventy-three thousand, six hundred fifty-seven".