16564641647557 has 2 divisors, whose sum is σ = 16564641647558. Its totient is φ = 16564641647556.

The previous prime is 16564641647551. The next prime is 16564641647573. The reversal of 16564641647557 is 75574614646561.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14768910325156 + 1795731322401 = 3843034^2 + 1340049^2 .

It is a cyclic number.

It is not a de Polignac number, because 16564641647557 - 2³⁵ = 16530281909189 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16564641647492 and 16564641647501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16564641647551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8282320823778 + 8282320823779.

It is an arithmetic number, because the mean of its divisors is an integer number (8282320823779).

Almost surely, 2^{16564641647557} is an apocalyptic number.

It is an amenable number.

16564641647557 is a deficient number, since it is larger than the sum of its proper divisors (1).

16564641647557 is an equidigital number, since it uses as much as digits as its factorization.

16564641647557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 508032000, while the sum is 67.

The spelling of 16564641647557 in words is "sixteen trillion, five hundred sixty-four billion, six hundred forty-one million, six hundred forty-seven thousand, five hundred fifty-seven".