21597628320 has 192 divisors, whose sum is σ = 79570512000. Its totient is φ = 5456222208.

The previous prime is 21597628279. The next prime is 21597628321. The reversal of 21597628320 is 2382679512.

21597628320 is a `hidden beast` number, since 2 + 1 + 597 + 6 + 28 + 32 + 0 = 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 (21597628321) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49485 + ... + 213644.

It is an arithmetic number, because the mean of its divisors is an integer number (414429750).

Almost surely, 2^21597628320 is an apocalyptic number.

21597628320 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 21597628320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39785256000).

21597628320 is an abundant number, since it is smaller than the sum of its proper divisors (57972883680).

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

21597628320 is a wasteful number, since it uses less digits than its factorization.

21597628320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263172 (or 263158 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 21597628320 in words is "twenty-one billion, five hundred ninety-seven million, six hundred twenty-eight thousand, three hundred twenty".