13720665 has 32 divisors (see below), whose sum is σ = 25286400. Its totient is φ = 6223104.

The previous prime is 13720661. The next prime is 13720709. The reversal of 13720665 is 56602731.

13720665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 13720665 - 2² = 13720661 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13720661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15207 + ... + 16083.

It is an arithmetic number, because the mean of its divisors is an integer number (790200).

Almost surely, 2^13720665 is an apocalyptic number.

13720665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

13720665 is a deficient number, since it is larger than the sum of its proper divisors (11565735).

13720665 is a wasteful number, since it uses less digits than its factorization.

13720665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1041.

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 13720665 is about 3704.1416009651. The cubic root of 13720665 is about 239.4005002750.

It can be divided in two parts, 137 and 20665, that added together give a palindrome (20802).

The spelling of 13720665 in words is "thirteen million, seven hundred twenty thousand, six hundred sixty-five".