21132020 has 96 divisors (see below), whose sum is σ = 57915648. Its totient is φ = 6285312.

The previous prime is 21132011. The next prime is 21132061. The reversal of 21132020 is 2023112.

21132020 = 361² + 362² + ... + 479².

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21131992 and 21132010.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30599 + ... + 31281.

It is an arithmetic number, because the mean of its divisors is an integer number (603288).

Almost surely, 2^21132020 is an apocalyptic number.

21132020 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 21132020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28957824).

21132020 is an abundant number, since it is smaller than the sum of its proper divisors (36783628).

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

21132020 is a wasteful number, since it uses less digits than its factorization.

21132020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 729 (or 727 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21132020 is about 4596.9576896030. The cubic root of 21132020 is about 276.4693581994.

Adding to 21132020 its reverse (2023112), we get a palindrome (23155132).

The spelling of 21132020 in words is "twenty-one million, one hundred thirty-two thousand, twenty".