256461621629 has 2 divisors, whose sum is σ = 256461621630. Its totient is φ = 256461621628.

The previous prime is 256461621547. The next prime is 256461621667. The reversal of 256461621629 is 926126164652.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 254207556100 + 2254065529 = 504190^2 + 47477^2 .

It is a cyclic number.

It is not a de Polignac number, because 256461621629 - 2⁸ = 256461621373 is a prime.

It is a super-2 number, since 2×256461621629² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256461621029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128230810814 + 128230810815.

It is an arithmetic number, because the mean of its divisors is an integer number (128230810815).

Almost surely, 2^256461621629 is an apocalyptic number.

It is an amenable number.

256461621629 is a deficient number, since it is larger than the sum of its proper divisors (1).

256461621629 is an equidigital number, since it uses as much as digits as its factorization.

256461621629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1866240, while the sum is 50.

The spelling of 256461621629 in words is "two hundred fifty-six billion, four hundred sixty-one million, six hundred twenty-one thousand, six hundred twenty-nine".