21242434400 has 72 divisors (see below), whose sum is σ = 56572488504. Its totient is φ = 7724518400.

The previous prime is 21242434363. The next prime is 21242434403. The reversal of 21242434400 is 443424212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21242434400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242434403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1198157 + ... + 1215756.

It is an arithmetic number, because the mean of its divisors is an integer number (785729007).

Almost surely, 2^21242434400 is an apocalyptic number.

21242434400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21242434400 is an abundant number, since it is smaller than the sum of its proper divisors (35330054104).

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

21242434400 is a wasteful number, since it uses less digits than its factorization.

21242434400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2413944 (or 2413931 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 26.

Adding to 21242434400 its reverse (443424212), we get a palindrome (21685858612).

The spelling of 21242434400 in words is "twenty-one billion, two hundred forty-two million, four hundred thirty-four thousand, four hundred".