21131323400 has 96 divisors (see below), whose sum is σ = 54199432800. Its totient is φ = 7597708800.

The previous prime is 21131323399. The next prime is 21131323463. The reversal of 21131323400 is 432313112.

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 141839 + ... + 249761.

It is an arithmetic number, because the mean of its divisors is an integer number (564577425).

Almost surely, 2^21131323400 is an apocalyptic number.

21131323400 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 21131323400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27099716400).

21131323400 is an abundant number, since it is smaller than the sum of its proper divisors (33068109400).

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

21131323400 is a wasteful number, since it uses less digits than its factorization.

21131323400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108039 (or 108030 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21131323400 its reverse (432313112), we get a palindrome (21563636512).

The spelling of 21131323400 in words is "twenty-one billion, one hundred thirty-one million, three hundred twenty-three thousand, four hundred".