16556557617 has 48 divisors (see below), whose sum is σ = 24553598160. Its totient is φ = 10748215296.

The previous prime is 16556557553. The next prime is 16556557621. The reversal of 16556557617 is 71675565561.

16556557617 is a `hidden beast` number, since 1 + 6 + 5 + 5 + 65 + 576 + 1 + 7 = 666.

16556557617 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 3456381681 + 13100175936 = 58791^2 + 114456^2 .

It is not a de Polignac number, because 16556557617 - 2⁶ = 16556557553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16556557657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 15487359 + ... + 15488427.

It is an arithmetic number, because the mean of its divisors is an integer number (511533295).

Almost surely, 2^16556557617 is an apocalyptic number.

It is an amenable number.

16556557617 is a deficient number, since it is larger than the sum of its proper divisors (7997040543).

16556557617 is a wasteful number, since it uses less digits than its factorization.

16556557617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1442 (or 1439 counting only the distinct ones).

The product of its digits is 6615000, while the sum is 54.

The spelling of 16556557617 in words is "sixteen billion, five hundred fifty-six million, five hundred fifty-seven thousand, six hundred seventeen".