12391820 has 24 divisors (see below), whose sum is σ = 29740704. Its totient is φ = 4248576.

The previous prime is 12391811. The next prime is 12391831. The reversal of 12391820 is 2819321.

12391820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 12391820.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44117 + ... + 44396.

It is an arithmetic number, because the mean of its divisors is an integer number (1239196).

Almost surely, 2^12391820 is an apocalyptic number.

12391820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12391820 is an abundant number, since it is smaller than the sum of its proper divisors (17348884).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12391820 is a wasteful number, since it uses less digits than its factorization.

12391820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88529 (or 88527 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 12391820 is about 3520.2016987667. The cubic root of 12391820 is about 231.4079981857.

The spelling of 12391820 in words is "twelve million, three hundred ninety-one thousand, eight hundred twenty".