21132920 has 64 divisors (see below), whose sum is σ = 49658400. Its totient is φ = 8087040.

The previous prime is 21132907. The next prime is 21132931. The reversal of 21132920 is 2923112.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21132892 and 21132901.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 161255 + ... + 161385.

Almost surely, 2^21132920 is an apocalyptic number.

21132920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21132920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24829200).

21132920 is an abundant number, since it is smaller than the sum of its proper divisors (28525480).

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

21132920 is a wasteful number, since it uses less digits than its factorization.

21132920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 284 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21132920 is about 4597.0555793899. The cubic root of 21132920 is about 276.4732830315.

The spelling of 21132920 in words is "twenty-one million, one hundred thirty-two thousand, nine hundred twenty".