21618732 has 24 divisors (see below), whose sum is σ = 53099200. Its totient is φ = 6826896.

The previous prime is 21618703. The next prime is 21618739. The reversal of 21618732 is 23781612.

It is a self number, because there is not a number n which added to its sum of digits gives 21618732.

It is not an unprimeable number, because it can be changed into a prime (21618739) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47182 + ... + 47637.

Almost surely, 2^21618732 is an apocalyptic number.

It is an amenable number.

21618732 is an abundant number, since it is smaller than the sum of its proper divisors (31480468).

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

21618732 is a wasteful number, since it uses less digits than its factorization.

21618732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94845 (or 94843 counting only the distinct ones).

The product of its digits is 4032, while the sum is 30.

The square root of 21618732 is about 4649.5948210570. The cubic root of 21618732 is about 278.5758125355.

The spelling of 21618732 in words is "twenty-one million, six hundred eighteen thousand, seven hundred thirty-two".