12921978 has 16 divisors (see below), whose sum is σ = 26678016. Its totient is φ = 4168320.

The previous prime is 12921967. The next prime is 12922001. The reversal of 12921978 is 87912921.

12921978 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34551 + ... + 34922.

It is an arithmetic number, because the mean of its divisors is an integer number (1667376).

Almost surely, 2^12921978 is an apocalyptic number.

12921978 is an abundant number, since it is smaller than the sum of its proper divisors (13756038).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12921978 is a wasteful number, since it uses less digits than its factorization.

12921978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69509.

The product of its digits is 18144, while the sum is 39.

The square root of 12921978 is about 3594.7152877523. The cubic root of 12921978 is about 234.6621249803.

The spelling of 12921978 in words is "twelve million, nine hundred twenty-one thousand, nine hundred seventy-eight".