21124440400 has 60 divisors (see below), whose sum is σ = 58001685472. Its totient is φ = 7242664320.

The previous prime is 21124440383. The next prime is 21124440409. The reversal of 21124440400 is 404442112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124440409) 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, 3769422 + ... + 3775021.

Almost surely, 2^21124440400 is an apocalyptic number.

21124440400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21124440400 is an abundant number, since it is smaller than the sum of its proper divisors (36877245072).

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

21124440400 is a wasteful number, since it uses less digits than its factorization.

21124440400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7544468 (or 7544457 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

Adding to 21124440400 its reverse (404442112), we get a palindrome (21528882512).

The spelling of 21124440400 in words is "twenty-one billion, one hundred twenty-four million, four hundred forty thousand, four hundred".