12991951 has 4 divisors (see below), whose sum is σ = 14847952. Its totient is φ = 11135952.

The previous prime is 12991939. The next prime is 12991967. The reversal of 12991951 is 15919921.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 12991951 - 2⁹ = 12991439 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12991951.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12991931) 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, 927990 + ... + 928003.

It is an arithmetic number, because the mean of its divisors is an integer number (3711988).

Almost surely, 2^12991951 is an apocalyptic number.

12991951 is a deficient number, since it is larger than the sum of its proper divisors (1856001).

12991951 is an equidigital number, since it uses as much as digits as its factorization.

12991951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1856000.

The product of its digits is 7290, while the sum is 37.

The square root of 12991951 is about 3604.4349071664. The cubic root of 12991951 is about 235.0849308227.

The spelling of 12991951 in words is "twelve million, nine hundred ninety-one thousand, nine hundred fifty-one".