12391813 has 4 divisors (see below), whose sum is σ = 14162080. Its totient is φ = 10621548.

The previous prime is 12391811. The next prime is 12391831. The reversal of 12391813 is 31819321.

12391813 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

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 not a de Polignac number, because 12391813 - 2¹ = 12391811 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12391811) 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, 885123 + ... + 885136.

It is an arithmetic number, because the mean of its divisors is an integer number (3540520).

Almost surely, 2^12391813 is an apocalyptic number.

It is an amenable number.

12391813 is a deficient number, since it is larger than the sum of its proper divisors (1770267).

12391813 is an equidigital number, since it uses as much as digits as its factorization.

12391813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1770266.

The product of its digits is 1296, while the sum is 28.

The square root of 12391813 is about 3520.2007045054. The cubic root of 12391813 is about 231.4079546124.

The spelling of 12391813 in words is "twelve million, three hundred ninety-one thousand, eight hundred thirteen".