21513202400 has 108 divisors (see below), whose sum is σ = 52851836016. Its totient is φ = 8551065600.

The previous prime is 21513202379. The next prime is 21513202427. The reversal of 21513202400 is 420231512.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 46464569 + ... + 46465031.

It is an arithmetic number, because the mean of its divisors is an integer number (489368852).

Almost surely, 2^21513202400 is an apocalyptic number.

21513202400 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 21513202400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26425918008).

21513202400 is an abundant number, since it is smaller than the sum of its proper divisors (31338633616).

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

21513202400 is an equidigital number, since it uses as much as digits as its factorization.

21513202400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 965 (or 711 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

Adding to 21513202400 its reverse (420231512), we get a palindrome (21933433912).

The spelling of 21513202400 in words is "twenty-one billion, five hundred thirteen million, two hundred two thousand, four hundred".