12978116921 has 12 divisors (see below), whose sum is σ = 16469447760. Its totient is φ = 10112817960.

The previous prime is 12978116903. The next prime is 12978116927. The reversal of 12978116921 is 12961187921.

It is not a de Polignac number, because 12978116921 - 2²⁶ = 12911008057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12978116927) 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, 12038531 + ... + 12039608.

It is an arithmetic number, because the mean of its divisors is an integer number (1372453980).

Almost surely, 2^12978116921 is an apocalyptic number.

12978116921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12978116921 is a deficient number, since it is larger than the sum of its proper divisors (3491330839).

12978116921 is a wasteful number, since it uses less digits than its factorization.

12978116921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24078164 (or 24078157 counting only the distinct ones).

The product of its digits is 108864, while the sum is 47.

The spelling of 12978116921 in words is "twelve billion, nine hundred seventy-eight million, one hundred sixteen thousand, nine hundred twenty-one".