21164832 has 72 divisors (see below), whose sum is σ = 64828764. Its totient is φ = 6511104.

The previous prime is 21164827. The next prime is 21164833. The reversal of 21164832 is 23846112.

21164832 is a `hidden beast` number, since 2 + 11 + 648 + 3 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 21123216 + 41616 = 4596^2 + 204^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×21164832² = 895900227176448, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 21164796 and 21164805.

It is not an unprimeable number, because it can be changed into a prime (21164833) 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, 918 + ... + 6570.

Almost surely, 2^21164832 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 21164832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32414382).

21164832 is an abundant number, since it is smaller than the sum of its proper divisors (43663932).

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

21164832 is a wasteful number, since it uses less digits than its factorization.

21164832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5682 (or 5671 counting only the distinct ones).

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

The square root of 21164832 is about 4600.5251874107. The cubic root of 21164832 is about 276.6123768897.

The spelling of 21164832 in words is "twenty-one million, one hundred sixty-four thousand, eight hundred thirty-two".