21132400 has 60 divisors (see below), whose sum is σ = 53001072. Its totient is φ = 8081920.

The previous prime is 21132383. The next prime is 21132481. The reversal of 21132400 is 423112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8052 + ... + 10348.

Almost surely, 2^21132400 is an apocalyptic number.

21132400 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 21132400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26500536).

21132400 is an abundant number, since it is smaller than the sum of its proper divisors (31868672).

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

21132400 is a wasteful number, since it uses less digits than its factorization.

21132400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2338 (or 2327 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21132400 is about 4596.9990211006. Note that the first 3 decimals coincide. The cubic root of 21132400 is about 276.4710153643.

Adding to 21132400 its reverse (423112), we get a palindrome (21555512).

The spelling of 21132400 in words is "twenty-one million, one hundred thirty-two thousand, four hundred".