16564718557 has 4 divisors (see below), whose sum is σ = 16571574396. Its totient is φ = 16557862720.

The previous prime is 16564718551. The next prime is 16564718561. The reversal of 16564718557 is 75581746561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16174498041 + 390220516 = 127179^2 + 19754^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16564718557 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16564718498 and 16564718507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16564718551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3424294 + ... + 3429127.

It is an arithmetic number, because the mean of its divisors is an integer number (4142893599).

Almost surely, 2^16564718557 is an apocalyptic number.

It is an amenable number.

16564718557 is a deficient number, since it is larger than the sum of its proper divisors (6855839).

16564718557 is an equidigital number, since it uses as much as digits as its factorization.

16564718557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6855838.

The product of its digits is 7056000, while the sum is 55.

The spelling of 16564718557 in words is "sixteen billion, five hundred sixty-four million, seven hundred eighteen thousand, five hundred fifty-seven".