13565642661 has 12 divisors (see below), whose sum is σ = 19601844288. Its totient is φ = 9040518504.

The previous prime is 13565642647. The next prime is 13565642669. The reversal of 13565642661 is 16624656531.

13565642661 is a `hidden beast` number, since 1 + 3 + 5 + 6 + 564 + 26 + 61 = 666.

It is not a de Polignac number, because 13565642661 - 2¹⁰ = 13565641637 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13565642669) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 243645 + ... + 294098.

It is an arithmetic number, because the mean of its divisors is an integer number (1633487024).

Almost surely, 2^13565642661 is an apocalyptic number.

It is an amenable number.

13565642661 is a deficient number, since it is larger than the sum of its proper divisors (6036201627).

13565642661 is a wasteful number, since it uses less digits than its factorization.

13565642661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540552 (or 540549 counting only the distinct ones).

The product of its digits is 777600, while the sum is 45.

The spelling of 13565642661 in words is "thirteen billion, five hundred sixty-five million, six hundred forty-two thousand, six hundred sixty-one".