256661413 has 2 divisors, whose sum is σ = 256661414. Its totient is φ = 256661412.

The previous prime is 256661411. The next prime is 256661429. The reversal of 256661413 is 314166652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134050084 + 122611329 = 11578^2 + 11073^2 .

It is a cyclic number.

It is not a de Polignac number, because 256661413 - 2¹ = 256661411 is a prime.

Together with 256661411, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256661411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128330706 + 128330707.

It is an arithmetic number, because the mean of its divisors is an integer number (128330707).

Almost surely, 2^256661413 is an apocalyptic number.

It is an amenable number.

256661413 is a deficient number, since it is larger than the sum of its proper divisors (1).

256661413 is an equidigital number, since it uses as much as digits as its factorization.

256661413 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25920, while the sum is 34.

The square root of 256661413 is about 16020.6558230305. The cubic root of 256661413 is about 635.5067878572.

The spelling of 256661413 in words is "two hundred fifty-six million, six hundred sixty-one thousand, four hundred thirteen".