21320613288 has 320 divisors, whose sum is σ = 66814070400. Its totient is φ = 6309757440.

The previous prime is 21320613287. The next prime is 21320613361. The reversal of 21320613288 is 88231602312.

21320613288 is a `hidden beast` number, since 2 + 1 + 32 + 0 + 613 + 2 + 8 + 8 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21320613283) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 25718058 + ... + 25718886.

It is an arithmetic number, because the mean of its divisors is an integer number (208793970).

Almost surely, 2^21320613288 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21320613288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33407035200).

21320613288 is an abundant number, since it is smaller than the sum of its proper divisors (45493457112).

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

21320613288 is a wasteful number, since it uses less digits than its factorization.

21320613288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 974 (or 961 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 21320613288 in words is "twenty-one billion, three hundred twenty million, six hundred thirteen thousand, two hundred eighty-eight".