56561685857 has 2 divisors, whose sum is σ = 56561685858. Its totient is φ = 56561685856.

The previous prime is 56561685809. The next prime is 56561685899. The reversal of 56561685857 is 75858616565.

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., 44150834641 + 12410851216 = 210121^2 + 111404^2 .

It is a cyclic number.

It is not a de Polignac number, because 56561685857 - 2⁸ = 56561685601 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 56561685857.

It is not a weakly prime, because it can be changed into another prime (56561685157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28280842928 + 28280842929.

It is an arithmetic number, because the mean of its divisors is an integer number (28280842929).

Almost surely, 2^56561685857 is an apocalyptic number.

It is an amenable number.

56561685857 is a deficient number, since it is larger than the sum of its proper divisors (1).

56561685857 is an equidigital number, since it uses as much as digits as its factorization.

56561685857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480000, while the sum is 62.

The spelling of 56561685857 in words is "fifty-six billion, five hundred sixty-one million, six hundred eighty-five thousand, eight hundred fifty-seven".