21132120 has 64 divisors (see below), whose sum is σ = 63756000. Its totient is φ = 5603328.

The previous prime is 21132119. The next prime is 21132127. The reversal of 21132120 is 2123112.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21132096 and 21132105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21132127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27096 + ... + 27864.

Almost surely, 2^21132120 is an apocalyptic number.

21132120 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 21132120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31878000).

21132120 is an abundant number, since it is smaller than the sum of its proper divisors (42623880).

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

21132120 is a wasteful number, since it uses less digits than its factorization.

21132120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1012 (or 1008 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21132120 is about 4596.9685663489. The cubic root of 21132120 is about 276.4697942973.

Adding to 21132120 its reverse (2123112), we get a palindrome (23255232).

The spelling of 21132120 in words is "twenty-one million, one hundred thirty-two thousand, one hundred twenty".