22518021 has 16 divisors (see below), whose sum is σ = 31795200. Its totient is φ = 14136048.

The previous prime is 22518017. The next prime is 22518049. The reversal of 22518021 is 12081522.

It is a happy number.

It is not a de Polignac number, because 22518021 - 2² = 22518017 is a prime.

It is a super-2 number, since 2×22518021² = 1014122539512882, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22514021) 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, 9100 + ... + 11306.

It is an arithmetic number, because the mean of its divisors is an integer number (1987200).

Almost surely, 2^22518021 is an apocalyptic number.

It is an amenable number.

22518021 is a deficient number, since it is larger than the sum of its proper divisors (9277179).

22518021 is a wasteful number, since it uses less digits than its factorization.

22518021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2408.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 22518021 is about 4745.3156902360. The cubic root of 22518021 is about 282.3861592633.

Adding to 22518021 its reverse (12081522), we get a palindrome (34599543).

The spelling of 22518021 in words is "twenty-two million, five hundred eighteen thousand, twenty-one".