21613115520 has 256 divisors, whose sum is σ = 76686048000. Its totient is φ = 5752995840.

The previous prime is 21613115507. The next prime is 21613115567. The reversal of 21613115520 is 2551131612.

21613115520 is a `hidden beast` number, since 2 + 1 + 6 + 131 + 1 + 5 + 520 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15879640 + ... + 15881000.

It is an arithmetic number, because the mean of its divisors is an integer number (299554875).

Almost surely, 2^21613115520 is an apocalyptic number.

21613115520 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 21613115520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38343024000).

21613115520 is an abundant number, since it is smaller than the sum of its proper divisors (55072932480).

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

21613115520 is a wasteful number, since it uses less digits than its factorization.

21613115520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2308 (or 2290 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 21613115520 in words is "twenty-one billion, six hundred thirteen million, one hundred fifteen thousand, five hundred twenty".