256334625661 has 2 divisors, whose sum is σ = 256334625662. Its totient is φ = 256334625660.

The previous prime is 256334625623. The next prime is 256334625671. The reversal of 256334625661 is 166526433652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 144651669561 + 111682956100 = 380331^2 + 334190^2 .

It is a cyclic number.

It is not a de Polignac number, because 256334625661 - 2²³ = 256326237053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256334625601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128167312830 + 128167312831.

It is an arithmetic number, because the mean of its divisors is an integer number (128167312831).

Almost surely, 2^256334625661 is an apocalyptic number.

It is an amenable number.

256334625661 is a deficient number, since it is larger than the sum of its proper divisors (1).

256334625661 is an equidigital number, since it uses as much as digits as its factorization.

256334625661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4665600, while the sum is 49.

The spelling of 256334625661 in words is "two hundred fifty-six billion, three hundred thirty-four million, six hundred twenty-five thousand, six hundred sixty-one".