21508882560 has 768 divisors, whose sum is σ = 85433241600. Its totient is φ = 5173217280.

The previous prime is 21508882519. The next prime is 21508882567. The reversal of 21508882560 is 6528880512.

21508882560 is a `hidden beast` number, since 2 + 1 + 5 + 0 + 8 + 8 + 82 + 560 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21508882567) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 169361217 + ... + 169361343.

It is an arithmetic number, because the mean of its divisors is an integer number (111241200).

Almost surely, 2^21508882560 is an apocalyptic number.

21508882560 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 21508882560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42716620800).

21508882560 is an abundant number, since it is smaller than the sum of its proper divisors (63924359040).

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

21508882560 is an equidigital number, since it uses as much as digits as its factorization.

21508882560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 307200, while the sum is 45.

The spelling of 21508882560 in words is "twenty-one billion, five hundred eight million, eight hundred eighty-two thousand, five hundred sixty".