12939991 has 4 divisors (see below), whose sum is σ = 13152184. Its totient is φ = 12727800.

The previous prime is 12939967. The next prime is 12940001. The reversal of 12939991 is 19993921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19993921 = 17 ⋅1176113.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12939991 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 (12939391) 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, 106005 + ... + 106126.

It is an arithmetic number, because the mean of its divisors is an integer number (3288046).

Almost surely, 2^12939991 is an apocalyptic number.

12939991 is a deficient number, since it is larger than the sum of its proper divisors (212193).

12939991 is an equidigital number, since it uses as much as digits as its factorization.

12939991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212192.

The product of its digits is 39366, while the sum is 43.

The square root of 12939991 is about 3597.2198987551. The cubic root of 12939991 is about 234.7711125845.

The spelling of 12939991 in words is "twelve million, nine hundred thirty-nine thousand, nine hundred ninety-one".