12991239 has 8 divisors (see below), whose sum is σ = 19246320. Its totient is φ = 8660808.

The previous prime is 12991229. The next prime is 12991249. The reversal of 12991239 is 93219921.

It is a happy number.

12991239 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (12991229) and next prime (12991249).

It is not a de Polignac number, because 12991239 - 2¹¹ = 12989191 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12991229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 240552 + ... + 240605.

It is an arithmetic number, because the mean of its divisors is an integer number (2405790).

Almost surely, 2^12991239 is an apocalyptic number.

12991239 is a deficient number, since it is larger than the sum of its proper divisors (6255081).

12991239 is an equidigital number, since it uses as much as digits as its factorization.

12991239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481166 (or 481160 counting only the distinct ones).

The product of its digits is 8748, while the sum is 36.

The square root of 12991239 is about 3604.3361385975. The cubic root of 12991239 is about 235.0806362784.

The spelling of 12991239 in words is "twelve million, nine hundred ninety-one thousand, two hundred thirty-nine".