21072451400 has 384 divisors, whose sum is σ = 66805724160. Its totient is φ = 5968512000.

The previous prime is 21072451373. The next prime is 21072451417. The reversal of 21072451400 is 415427012.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 21072451400.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 13412615 + ... + 13414185.

It is an arithmetic number, because the mean of its divisors is an integer number (173973240).

Almost surely, 2^21072451400 is an apocalyptic number.

21072451400 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 21072451400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33402862080).

21072451400 is an abundant number, since it is smaller than the sum of its proper divisors (45733272760).

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

21072451400 is a wasteful number, since it uses less digits than its factorization.

21072451400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1685 (or 1676 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 26.

Adding to 21072451400 its reverse (415427012), we get a palindrome (21487878412).

The spelling of 21072451400 in words is "twenty-one billion, seventy-two million, four hundred fifty-one thousand, four hundred".