21553250320 has 80 divisors (see below), whose sum is σ = 59760103680. Its totient is φ = 7068390912.

The previous prime is 21553250317. The next prime is 21553250321. The reversal of 21553250320 is 2305235512.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21553250321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 823815 + ... + 849574.

It is an arithmetic number, because the mean of its divisors is an integer number (747001296).

Almost surely, 2^21553250320 is an apocalyptic number.

21553250320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21553250320 is an abundant number, since it is smaller than the sum of its proper divisors (38206853360).

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

21553250320 is a wasteful number, since it uses less digits than its factorization.

21553250320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1673432 (or 1673426 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 28.

Adding to 21553250320 its reverse (2305235512), we get a palindrome (23858485832).

The spelling of 21553250320 in words is "twenty-one billion, five hundred fifty-three million, two hundred fifty thousand, three hundred twenty".