13626721 has 4 divisors (see below), whose sum is σ = 13634244. Its totient is φ = 13619200.

The previous prime is 13626713. The next prime is 13626731. The reversal of 13626721 is 12762631.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12327121 + 1299600 = 3511^2 + 1140^2 .

It is a cyclic number.

It is not a de Polignac number, because 13626721 - 2³ = 13626713 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13626721.

It is not an unprimeable number, because it can be changed into a prime (13626731) 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, 801 + ... + 5281.

It is an arithmetic number, because the mean of its divisors is an integer number (3408561).

Almost surely, 2^13626721 is an apocalyptic number.

It is an amenable number.

13626721 is a deficient number, since it is larger than the sum of its proper divisors (7523).

13626721 is an equidigital number, since it uses as much as digits as its factorization.

13626721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7522.

The product of its digits is 3024, while the sum is 28.

The square root of 13626721 is about 3691.4388793531. The cubic root of 13626721 is about 238.8528648602.

The spelling of 13626721 in words is "thirteen million, six hundred twenty-six thousand, seven hundred twenty-one".