21992518 has 8 divisors (see below), whose sum is σ = 33117912. Its totient is φ = 10953216.

The previous prime is 21992501. The next prime is 21992521. The reversal of 21992518 is 81529912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20880 + ... + 21907.

It is an arithmetic number, because the mean of its divisors is an integer number (4139739).

Almost surely, 2^21992518 is an apocalyptic number.

21992518 is a deficient number, since it is larger than the sum of its proper divisors (11125394).

21992518 is a wasteful number, since it uses less digits than its factorization.

21992518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43046.

The product of its digits is 12960, while the sum is 37.

The square root of 21992518 is about 4689.6181081193. The cubic root of 21992518 is about 280.1721645271.

The spelling of 21992518 in words is "twenty-one million, nine hundred ninety-two thousand, five hundred eighteen".