21008056320 has 320 divisors, whose sum is σ = 75364201440. Its totient is φ = 5598609408.

The previous prime is 21008056301. The next prime is 21008056331. The reversal of 21008056320 is 2365080012.

21008056320 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 80 + 563 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 13270249 + ... + 13271831.

Almost surely, 2^21008056320 is an apocalyptic number.

21008056320 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 21008056320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37682100720).

21008056320 is an abundant number, since it is smaller than the sum of its proper divisors (54356145120).

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

21008056320 is an frugal number, since it uses more digits than its factorization.

21008056320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1630 (or 1593 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The spelling of 21008056320 in words is "twenty-one billion, eight million, fifty-six thousand, three hundred twenty".