21687613320 has 128 divisors (see below), whose sum is σ = 68981673600. Its totient is φ = 5435928576.

The previous prime is 21687613313. The next prime is 21687613331. The reversal of 21687613320 is 2331678612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1619211 + ... + 1632549.

It is an arithmetic number, because the mean of its divisors is an integer number (538919325).

Almost surely, 2^21687613320 is an apocalyptic number.

21687613320 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 21687613320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34490836800).

21687613320 is an abundant number, since it is smaller than the sum of its proper divisors (47294060280).

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

21687613320 is a wasteful number, since it uses less digits than its factorization.

21687613320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14167 (or 14163 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 39.

The spelling of 21687613320 in words is "twenty-one billion, six hundred eighty-seven million, six hundred thirteen thousand, three hundred twenty".