13637561 has 4 divisors (see below), whose sum is σ = 15585792. Its totient is φ = 11689332.

The previous prime is 13637539. The next prime is 13637581. The reversal of 13637561 is 16573631.

13637561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16573631 = 59 ⋅280909.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13637561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13637501) 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, 974105 + ... + 974118.

It is an arithmetic number, because the mean of its divisors is an integer number (3896448).

Almost surely, 2^13637561 is an apocalyptic number.

It is an amenable number.

13637561 is a deficient number, since it is larger than the sum of its proper divisors (1948231).

13637561 is an equidigital number, since it uses as much as digits as its factorization.

13637561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1948230.

The product of its digits is 11340, while the sum is 32.

The square root of 13637561 is about 3692.9068496240. The cubic root of 13637561 is about 238.9161835608.

The spelling of 13637561 in words is "thirteen million, six hundred thirty-seven thousand, five hundred sixty-one".