20959818 has 32 divisors (see below), whose sum is σ = 45964800. Its totient is φ = 6318960.

The previous prime is 20959787. The next prime is 20959819. The reversal of 20959818 is 81895902.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20959818.

It is not an unprimeable number, because it can be changed into a prime (20959819) 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, 14283 + ... + 15681.

It is an arithmetic number, because the mean of its divisors is an integer number (1436400).

Almost surely, 2^20959818 is an apocalyptic number.

20959818 is an abundant number, since it is smaller than the sum of its proper divisors (25004982).

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

20959818 is a wasteful number, since it uses less digits than its factorization.

20959818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1642.

The product of its (nonzero) digits is 51840, while the sum is 42.

The square root of 20959818 is about 4578.1893800934. The cubic root of 20959818 is about 275.7163384738.

The spelling of 20959818 in words is "twenty million, nine hundred fifty-nine thousand, eight hundred eighteen".