56668013561 has 2 divisors, whose sum is σ = 56668013562. Its totient is φ = 56668013560.

The previous prime is 56668013509. The next prime is 56668013581. The reversal of 56668013561 is 16531086665.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43735775161 + 12932238400 = 209131^2 + 113720^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56668013561 is a prime.

It is a super-2 number, since 2×56668013561² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (56668013581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28334006780 + 28334006781.

It is an arithmetic number, because the mean of its divisors is an integer number (28334006781).

Almost surely, 2^56668013561 is an apocalyptic number.

It is an amenable number.

56668013561 is a deficient number, since it is larger than the sum of its proper divisors (1).

56668013561 is an equidigital number, since it uses as much as digits as its factorization.

56668013561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 777600, while the sum is 47.

The spelling of 56668013561 in words is "fifty-six billion, six hundred sixty-eight million, thirteen thousand, five hundred sixty-one".