21136512400 has 240 divisors, whose sum is σ = 54860952960. Its totient is φ = 7820736000.

The previous prime is 21136512281. The next prime is 21136512421. The reversal of 21136512400 is 421563112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 209272350 + ... + 209272450.

It is an arithmetic number, because the mean of its divisors is an integer number (228587304).

Almost surely, 2^21136512400 is an apocalyptic number.

21136512400 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 21136512400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27430476480).

21136512400 is an abundant number, since it is smaller than the sum of its proper divisors (33724440560).

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

21136512400 is a wasteful number, since it uses less digits than its factorization.

21136512400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231 (or 174 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The spelling of 21136512400 in words is "twenty-one billion, one hundred thirty-six million, five hundred twelve thousand, four hundred".