21998924 has 18 divisors (see below), whose sum is σ = 39083772. Its totient is φ = 10834600.

The previous prime is 21998923. The next prime is 21998927. The reversal of 21998924 is 42989912.

It is not an unprimeable number, because it can be changed into a prime (21998923) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19619 + ... + 20709.

Almost surely, 2^21998924 is an apocalyptic number.

It is an amenable number.

21998924 is a deficient number, since it is larger than the sum of its proper divisors (17084848).

21998924 is a wasteful number, since it uses less digits than its factorization.

21998924 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1237 (or 1164 counting only the distinct ones).

The product of its digits is 93312, while the sum is 44.

The square root of 21998924 is about 4690.3010564355. The cubic root of 21998924 is about 280.1993648178.

It can be divided in two parts, 21998 and 924, that added together give a palindrome (22922).

The spelling of 21998924 in words is "twenty-one million, nine hundred ninety-eight thousand, nine hundred twenty-four".