121979817 has 16 divisors (see below), whose sum is σ = 182138880. Its totient is φ = 80677296.

The previous prime is 121979807. The next prime is 121979831. The reversal of 121979817 is 718979121.

It is a happy number.

It is not a de Polignac number, because 121979817 - 2¹⁶ = 121914281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121979807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14358 + ... + 21215.

It is an arithmetic number, because the mean of its divisors is an integer number (11383680).

Almost surely, 2^121979817 is an apocalyptic number.

It is an amenable number.

121979817 is a deficient number, since it is larger than the sum of its proper divisors (60159063).

121979817 is a wasteful number, since it uses less digits than its factorization.

121979817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35709 (or 35703 counting only the distinct ones).

The product of its digits is 63504, while the sum is 45.

The square root of 121979817 is about 11044.4473379160. The cubic root of 121979817 is about 495.9402148393.

The spelling of 121979817 in words is "one hundred twenty-one million, nine hundred seventy-nine thousand, eight hundred seventeen".