13368721 has 4 divisors (see below), whose sum is σ = 13376052. Its totient is φ = 13361392.

The previous prime is 13368713. The next prime is 13368731. The reversal of 13368721 is 12786331.

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 11833600 + 1535121 = 3440^2 + 1239^2 .

It is a cyclic number.

It is not a de Polignac number, because 13368721 - 2³ = 13368713 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13368731) 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, 1455 + ... + 5371.

It is an arithmetic number, because the mean of its divisors is an integer number (3344013).

Almost surely, 2^13368721 is an apocalyptic number.

It is an amenable number.

13368721 is a deficient number, since it is larger than the sum of its proper divisors (7331).

13368721 is an equidigital number, since it uses as much as digits as its factorization.

13368721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7330.

The product of its digits is 6048, while the sum is 31.

The square root of 13368721 is about 3656.3261615999. The cubic root of 13368721 is about 237.3358185698.

The spelling of 13368721 in words is "thirteen million, three hundred sixty-eight thousand, seven hundred twenty-one".