56821360661 has 6 divisors (see below), whose sum is σ = 61528455810. Its totient is φ = 52450486608.

The previous prime is 56821360649. The next prime is 56821360669. The reversal of 56821360661 is 16606312865.

It can be written as a sum of positive squares in 3 ways, for example, as 1458094225 + 55363266436 = 38185^2 + 235294^2 .

It is a de Polignac number, because none of the positive numbers 2^k-56821360661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56821360669) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 168110366 + ... + 168110703.

It is an arithmetic number, because the mean of its divisors is an integer number (10254742635).

Almost surely, 2^56821360661 is an apocalyptic number.

It is an amenable number.

56821360661 is a deficient number, since it is larger than the sum of its proper divisors (4707095149).

56821360661 is a wasteful number, since it uses less digits than its factorization.

56821360661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336221095 (or 336221082 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 44.

The spelling of 56821360661 in words is "fifty-six billion, eight hundred twenty-one million, three hundred sixty thousand, six hundred sixty-one".