2166205617639 has 96 divisors (see below), whose sum is σ = 3964892672000. Its totient is φ = 1134853312320.

The previous prime is 2166205617623. The next prime is 2166205617721. The reversal of 2166205617639 is 9367165026612.

2166205617639 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 2 + 0 + 561 + 76 + 3 + 9 = 666.

It is not a de Polignac number, because 2166205617639 - 2⁴ = 2166205617623 is a prime.

It is a super-2 number, since 2×2166205617639² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166205617539) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1222557 + ... + 2413929.

Almost surely, 2^{2166205617639} is an apocalyptic number.

2166205617639 is a deficient number, since it is larger than the sum of its proper divisors (1798687054361).

2166205617639 is a wasteful number, since it uses less digits than its factorization.

2166205617639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1191450 (or 1191433 counting only the distinct ones).

The product of its (nonzero) digits is 4898880, while the sum is 54.

The spelling of 2166205617639 in words is "two trillion, one hundred sixty-six billion, two hundred five million, six hundred seventeen thousand, six hundred thirty-nine".