21518932 has 12 divisors (see below), whose sum is σ = 38576916. Its totient is φ = 10496960.

The previous prime is 21518881. The next prime is 21518933. The reversal of 21518932 is 23981512.

It can be written as a sum of positive squares in 2 ways, for example, as 12362256 + 9156676 = 3516^2 + 3026^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21518894 and 21518903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21518933) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65443 + ... + 65770.

It is an arithmetic number, because the mean of its divisors is an integer number (3214743).

Almost surely, 2^21518932 is an apocalyptic number.

It is an amenable number.

21518932 is a deficient number, since it is larger than the sum of its proper divisors (17057984).

21518932 is a wasteful number, since it uses less digits than its factorization.

21518932 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131258 (or 131256 counting only the distinct ones).

The product of its digits is 4320, while the sum is 31.

The square root of 21518932 is about 4638.8502885952. The cubic root of 21518932 is about 278.1464818151.

The spelling of 21518932 in words is "twenty-one million, five hundred eighteen thousand, nine hundred thirty-two".