20117979 has 42 divisors (see below), whose sum is σ = 35686820. Its totient is φ = 10890936.

The previous prime is 20117971. The next prime is 20118011. The reversal of 20117979 is 97971102.

It is not a de Polignac number, because 20117979 - 2³ = 20117971 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is a zygodrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (20117971) by changing a digit.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 1058832 + ... + 1058850.

Almost surely, 2^20117979 is an apocalyptic number.

20117979 is a deficient number, since it is larger than the sum of its proper divisors (15568841).

20117979 is an frugal number, since it uses more digits than its factorization.

20117979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 36.

The square root of 20117979 is about 4485.3070129034. The cubic root of 20117979 is about 271.9744560427.

The spelling of 20117979 in words is "twenty million, one hundred seventeen thousand, nine hundred seventy-nine".