20979618 has 32 divisors (see below), whose sum is σ = 46896192. Its totient is φ = 6201600.

The previous prime is 20979613. The next prime is 20979641. The reversal of 20979618 is 81697902.

It is a self number, because there is not a number n which added to its sum of digits gives 20979618.

It is not an unprimeable number, because it can be changed into a prime (20979613) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1171 + ... + 6582.

It is an arithmetic number, because the mean of its divisors is an integer number (1465506).

Almost surely, 2^20979618 is an apocalyptic number.

20979618 is an abundant number, since it is smaller than the sum of its proper divisors (25916574).

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

20979618 is a wasteful number, since it uses less digits than its factorization.

20979618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7810.

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 20979618 is about 4580.3512965710. The cubic root of 20979618 is about 275.8031309795.

The spelling of 20979618 in words is "twenty million, nine hundred seventy-nine thousand, six hundred eighteen".