21809884320 has 864 divisors, whose sum is σ = 91961775360. Its totient is φ = 4683571200.

The previous prime is 21809884289. The next prime is 21809884379. The reversal of 21809884320 is 2348890812.

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

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 144436245 + ... + 144436395.

It is an arithmetic number, because the mean of its divisors is an integer number (106437240).

Almost surely, 2^21809884320 is an apocalyptic number.

21809884320 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 21809884320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45980887680).

21809884320 is an abundant number, since it is smaller than the sum of its proper divisors (70151891040).

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

21809884320 is a wasteful number, since it uses less digits than its factorization.

21809884320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 21809884320 in words is "twenty-one billion, eight hundred nine million, eight hundred eighty-four thousand, three hundred twenty".