13806521 has 4 divisors (see below), whose sum is σ = 14533200. Its totient is φ = 13079844.

The previous prime is 13806503. The next prime is 13806539. The reversal of 13806521 is 12560831.

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.

It is an interprime number because it is at equal distance from previous prime (13806503) and next prime (13806539).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13806521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13806571) 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, 363311 + ... + 363348.

It is an arithmetic number, because the mean of its divisors is an integer number (3633300).

Almost surely, 2^13806521 is an apocalyptic number.

It is an amenable number.

13806521 is a deficient number, since it is larger than the sum of its proper divisors (726679).

13806521 is an equidigital number, since it uses as much as digits as its factorization.

13806521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 726678.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 13806521 is about 3715.7127176357. The cubic root of 13806521 is about 239.8988057178.

The spelling of 13806521 in words is "thirteen million, eight hundred six thousand, five hundred twenty-one".