12991917 has 8 divisors (see below), whose sum is σ = 17360640. Its totient is φ = 8642240.

The previous prime is 12991879. The next prime is 12991931. The reversal of 12991917 is 71919921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12991917 - 2⁸ = 12991661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12991967) 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, 3084 + ... + 5957.

It is an arithmetic number, because the mean of its divisors is an integer number (2170080).

Almost surely, 2^12991917 is an apocalyptic number.

It is an amenable number.

12991917 is a deficient number, since it is larger than the sum of its proper divisors (4368723).

12991917 is an equidigital number, since it uses as much as digits as its factorization.

12991917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9523.

The product of its digits is 10206, while the sum is 39.

The square root of 12991917 is about 3604.4301907514. The cubic root of 12991917 is about 235.0847257497.

The spelling of 12991917 in words is "twelve million, nine hundred ninety-one thousand, nine hundred seventeen".