12691999 has 12 divisors (see below), whose sum is σ = 13327104. Its totient is φ = 12083904.

The previous prime is 12691997. The next prime is 12692027. The reversal of 12691999 is 99919621.

12691999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12691999 - 2¹ = 12691997 is a prime.

It is a super-2 number, since 2×12691999² = 322173677232002, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12691997) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 99874 + ... + 100000.

It is an arithmetic number, because the mean of its divisors is an integer number (1110592).

Almost surely, 2^12691999 is an apocalyptic number.

12691999 is a deficient number, since it is larger than the sum of its proper divisors (635105).

12691999 is an equidigital number, since it uses as much as digits as its factorization.

12691999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 237 counting only the distinct ones).

The product of its digits is 78732, while the sum is 46.

The square root of 12691999 is about 3562.5831920111. The cubic root of 12691999 is about 233.2616498621.

The spelling of 12691999 in words is "twelve million, six hundred ninety-one thousand, nine hundred ninety-nine".