13666617891 has 16 divisors (see below), whose sum is σ = 20266482720. Its totient is φ = 9102240000.

The previous prime is 13666617859. The next prime is 13666617893. The reversal of 13666617891 is 19871666631.

It is not a de Polignac number, because 13666617891 - 2⁵ = 13666617859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (13666617893) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 217110 + ... + 272891.

It is an arithmetic number, because the mean of its divisors is an integer number (1266655170).

Almost surely, 2^13666617891 is an apocalyptic number.

13666617891 is a deficient number, since it is larger than the sum of its proper divisors (6599864829).

13666617891 is a wasteful number, since it uses less digits than its factorization.

13666617891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491043 (or 491037 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 54.

The spelling of 13666617891 in words is "thirteen billion, six hundred sixty-six million, six hundred seventeen thousand, eight hundred ninety-one".