21037507920 has 800 divisors, whose sum is σ = 87295912704. Its totient is φ = 4628275200.

The previous prime is 21037507913. The next prime is 21037507943. The reversal of 21037507920 is 2970573012.

21037507920 is a `hidden beast` number, since 210 + 375 + 0 + 79 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 67644565 + ... + 67644875.

Almost surely, 2^21037507920 is an apocalyptic number.

21037507920 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 21037507920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43647956352).

21037507920 is an abundant number, since it is smaller than the sum of its proper divisors (66258404784).

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

21037507920 is a wasteful number, since it uses less digits than its factorization.

21037507920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433 (or 418 counting only the distinct ones).

The product of its (nonzero) digits is 26460, while the sum is 36.

The spelling of 21037507920 in words is "twenty-one billion, thirty-seven million, five hundred seven thousand, nine hundred twenty".