21563578080 has 768 divisors, whose sum is σ = 86124487680. Its totient is φ = 4993228800.

The previous prime is 21563578063. The next prime is 21563578093. The reversal of 21563578080 is 8087536512.

21563578080 is a `hidden beast` number, since 2 + 1 + 5 + 635 + 7 + 8 + 0 + 8 + 0 = 666.

It is a super-2 number, since 2×21563578080² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 127 ways as a sum of consecutive naturals, for example, 124644874 + ... + 124645046.

It is an arithmetic number, because the mean of its divisors is an integer number (112141260).

Almost surely, 2^21563578080 is an apocalyptic number.

21563578080 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 21563578080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43062243840).

21563578080 is an abundant number, since it is smaller than the sum of its proper divisors (64560909600).

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

21563578080 is a wasteful number, since it uses less digits than its factorization.

21563578080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312 (or 298 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 21563578080 in words is "twenty-one billion, five hundred sixty-three million, five hundred seventy-eight thousand, eighty".