21164328 has 112 divisors (see below), whose sum is σ = 62956800. Its totient is φ = 6648480.

The previous prime is 21164327. The next prime is 21164357. The reversal of 21164328 is 82346112.

21164328 is a `hidden beast` number, since 2 + 11 + 643 + 2 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21164321) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 110713 + ... + 110903.

Almost surely, 2^21164328 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21164328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31478400).

21164328 is an abundant number, since it is smaller than the sum of its proper divisors (41792472).

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

21164328 is a wasteful number, since it uses less digits than its factorization.

21164328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 215 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21164328 is about 4600.4704107298. The cubic root of 21164328 is about 276.6101812073.

The spelling of 21164328 in words is "twenty-one million, one hundred sixty-four thousand, three hundred twenty-eight".