21023118 has 32 divisors (see below), whose sum is σ = 49468320. Its totient is φ = 6595200.

The previous prime is 21023117. The next prime is 21023137. The reversal of 21023118 is 81132012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 21023118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023111) 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, 10533 + ... + 12368.

It is an arithmetic number, because the mean of its divisors is an integer number (1545885).

Almost surely, 2^21023118 is an apocalyptic number.

21023118 is an abundant number, since it is smaller than the sum of its proper divisors (28445202).

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

21023118 is a wasteful number, since it uses less digits than its factorization.

21023118 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22929 (or 22923 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 21023118 is about 4585.0973817357. The cubic root of 21023118 is about 275.9936198903.

The spelling of 21023118 in words is "twenty-one million, twenty-three thousand, one hundred eighteen".