12912181 has 4 divisors (see below), whose sum is σ = 12919500. Its totient is φ = 12904864.

The previous prime is 12912157. The next prime is 12912187. The reversal of 12912181 is 18121921.

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 167281 + 12744900 = 409^2 + 3570^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12912181 is a prime.

It is a super-2 number, since 2×12912181² = 333448836353522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12912187) 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, 795 + ... + 5143.

It is an arithmetic number, because the mean of its divisors is an integer number (3229875).

Almost surely, 2^12912181 is an apocalyptic number.

It is an amenable number.

12912181 is a deficient number, since it is larger than the sum of its proper divisors (7319).

12912181 is an equidigital number, since it uses as much as digits as its factorization.

12912181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7318.

The product of its digits is 288, while the sum is 25.

The square root of 12912181 is about 3593.3523345200. The cubic root of 12912181 is about 234.6028057314.

The spelling of 12912181 in words is "twelve million, nine hundred twelve thousand, one hundred eighty-one".