21037520400 has 480 divisors, whose sum is σ = 80207366400. Its totient is φ = 4660592640.

The previous prime is 21037520393. The next prime is 21037520401. The reversal of 21037520400 is 402573012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21037520401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 6097876 + ... + 6101324.

It is an arithmetic number, because the mean of its divisors is an integer number (167098680).

Almost surely, 2^21037520400 is an apocalyptic number.

21037520400 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 21037520400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40103683200).

21037520400 is an abundant number, since it is smaller than the sum of its proper divisors (59169846000).

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

21037520400 is a wasteful number, since it uses less digits than its factorization.

21037520400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3523 (or 3512 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The spelling of 21037520400 in words is "twenty-one billion, thirty-seven million, five hundred twenty thousand, four hundred".