21920600320 has 144 divisors (see below), whose sum is σ = 53425295280. Its totient is φ = 8616148992.

The previous prime is 21920600291. The next prime is 21920600323. The reversal of 21920600320 is 2300602912.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 632623104 + 21287977216 = 25152^2 + 145904^2 .

It is not an unprimeable number, because it can be changed into a prime (21920600323) 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, 21986062 + ... + 21987058.

It is an arithmetic number, because the mean of its divisors is an integer number (371008995).

Almost surely, 2^21920600320 is an apocalyptic number.

21920600320 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 21920600320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26712647640).

21920600320 is an abundant number, since it is smaller than the sum of its proper divisors (31504694960).

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

21920600320 is an equidigital number, since it uses as much as digits as its factorization.

21920600320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300 (or 1286 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 25.

The spelling of 21920600320 in words is "twenty-one billion, nine hundred twenty million, six hundred thousand, three hundred twenty".