21204412400 has 30 divisors (see below), whose sum is σ = 50943601752. Its totient is φ = 8481764800.

The previous prime is 21204412387. The next prime is 21204412403. The reversal of 21204412400 is 421440212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204412403) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 26505116 + ... + 26505915.

Almost surely, 2^21204412400 is an apocalyptic number.

21204412400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21204412400 is an abundant number, since it is smaller than the sum of its proper divisors (29739189352).

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

21204412400 is a wasteful number, since it uses less digits than its factorization.

21204412400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53011049 (or 53011038 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21204412400 its reverse (421440212), we get a palindrome (21625852612).

The spelling of 21204412400 in words is "twenty-one billion, two hundred four million, four hundred twelve thousand, four hundred".