121981978 has 16 divisors (see below), whose sum is σ = 186224256. Its totient is φ = 59914080.

The previous prime is 121981963. The next prime is 121981999. The reversal of 121981978 is 879189121.

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, 38025 + ... + 41107.

It is an arithmetic number, because the mean of its divisors is an integer number (11639016).

Almost surely, 2^121981978 is an apocalyptic number.

121981978 is a deficient number, since it is larger than the sum of its proper divisors (64242278).

121981978 is a wasteful number, since it uses less digits than its factorization.

121981978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3429.

The product of its digits is 72576, while the sum is 46.

The square root of 121981978 is about 11044.5451694490. The cubic root of 121981978 is about 495.9431435218.

The spelling of 121981978 in words is "one hundred twenty-one million, nine hundred eighty-one thousand, nine hundred seventy-eight".