21659364 has 36 divisors (see below), whose sum is σ = 54930876. Its totient is φ = 7195968.

The previous prime is 21659347. The next prime is 21659369. The reversal of 21659364 is 46395612.

It is a happy number.

21659364 is a `hidden beast` number, since 2 + 1 + 6 + 593 + 64 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12659364 + 9000000 = 3558^2 + 3000^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21659369) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12622 + ... + 14234.

Almost surely, 2^21659364 is an apocalyptic number.

It is an amenable number.

21659364 is an abundant number, since it is smaller than the sum of its proper divisors (33271512).

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

21659364 is a wasteful number, since it uses less digits than its factorization.

21659364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1996 (or 1991 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21659364 is about 4653.9621829147. The cubic root of 21659364 is about 278.7502293093.

The spelling of 21659364 in words is "twenty-one million, six hundred fifty-nine thousand, three hundred sixty-four".