13155921 has 6 divisors (see below), whose sum is σ = 19003010. Its totient is φ = 8770608.

The previous prime is 13155917. The next prime is 13155929. The reversal of 13155921 is 12955131.

13155921 is digitally balanced in base 2, base 3 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 9235521 + 3920400 = 3039^2 + 1980^2 .

It is not a de Polignac number, because 13155921 - 2² = 13155917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13155929) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 730876 + ... + 730893.

Almost surely, 2^13155921 is an apocalyptic number.

It is an amenable number.

13155921 is a deficient number, since it is larger than the sum of its proper divisors (5847089).

13155921 is a wasteful number, since it uses less digits than its factorization.

13155921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1461775 (or 1461772 counting only the distinct ones).

The product of its digits is 1350, while the sum is 27.

The square root of 13155921 is about 3627.1091794982. The cubic root of 13155921 is about 236.0697928694.

The spelling of 13155921 in words is "thirteen million, one hundred fifty-five thousand, nine hundred twenty-one".