12911521 has 4 divisors (see below), whose sum is σ = 14756032. Its totient is φ = 11067012.

The previous prime is 12911519. The next prime is 12911527. The reversal of 12911521 is 12511921.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12511921 = 179 ⋅69899.

It is a cyclic number.

It is not a de Polignac number, because 12911521 - 2¹ = 12911519 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12911492 and 12911501.

It is not an unprimeable number, because it can be changed into a prime (12911527) 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, 922245 + ... + 922258.

It is an arithmetic number, because the mean of its divisors is an integer number (3689008).

Almost surely, 2^12911521 is an apocalyptic number.

It is an amenable number.

12911521 is a deficient number, since it is larger than the sum of its proper divisors (1844511).

12911521 is an equidigital number, since it uses as much as digits as its factorization.

12911521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1844510.

The product of its digits is 180, while the sum is 22.

The square root of 12911521 is about 3593.2604970973. The cubic root of 12911521 is about 234.5988084596.

The spelling of 12911521 in words is "twelve million, nine hundred eleven thousand, five hundred twenty-one".