12399891 has 24 divisors (see below), whose sum is σ = 19535040. Its totient is φ = 6974352.

The previous prime is 12399883. The next prime is 12399901. The reversal of 12399891 is 19899321.

It is not a de Polignac number, because 12399891 - 2³ = 12399883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12399811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9220 + ... + 10478.

It is an arithmetic number, because the mean of its divisors is an integer number (813960).

Almost surely, 2^12399891 is an apocalyptic number.

12399891 is a deficient number, since it is larger than the sum of its proper divisors (7135149).

12399891 is a wasteful number, since it uses less digits than its factorization.

12399891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1343 (or 1336 counting only the distinct ones).

The product of its digits is 34992, while the sum is 42.

The square root of 12399891 is about 3521.3478953378. The cubic root of 12399891 is about 231.4582272511.

The spelling of 12399891 in words is "twelve million, three hundred ninety-nine thousand, eight hundred ninety-one".