13565921 has 4 divisors (see below), whose sum is σ = 13577472. Its totient is φ = 13554372.

The previous prime is 13565897. The next prime is 13565953. The reversal of 13565921 is 12956531.

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 a cyclic number.

It is not a de Polignac number, because 13565921 - 2⁶ = 13565857 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13565971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3785 + ... + 6438.

It is an arithmetic number, because the mean of its divisors is an integer number (3394368).

Almost surely, 2^13565921 is an apocalyptic number.

It is an amenable number.

13565921 is a deficient number, since it is larger than the sum of its proper divisors (11551).

13565921 is a wasteful number, since it uses less digits than its factorization.

13565921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11550.

The product of its digits is 8100, while the sum is 32.

The square root of 13565921 is about 3683.1944016030. The cubic root of 13565921 is about 238.4970955730.

The spelling of 13565921 in words is "thirteen million, five hundred sixty-five thousand, nine hundred twenty-one".