121617978 has 16 divisors (see below), whose sum is σ = 243344736. Its totient is φ = 40521200.

The previous prime is 121617961. The next prime is 121617989. The reversal of 121617978 is 879716121.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21553 + ... + 26603.

It is an arithmetic number, because the mean of its divisors is an integer number (15209046).

Almost surely, 2^121617978 is an apocalyptic number.

121617978 is an abundant number, since it is smaller than the sum of its proper divisors (121726758).

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

121617978 is a wasteful number, since it uses less digits than its factorization.

121617978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9069.

The product of its digits is 42336, while the sum is 42.

The square root of 121617978 is about 11028.0541347964. The cubic root of 121617978 is about 495.4493460805.

The spelling of 121617978 in words is "one hundred twenty-one million, six hundred seventeen thousand, nine hundred seventy-eight".