21097319320 has 128 divisors (see below), whose sum is σ = 59481216000. Its totient is φ = 6542553600.

The previous prime is 21097319317. The next prime is 21097319371. The reversal of 21097319320 is 2391379012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21097319320.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 595710 + ... + 630130.

It is an arithmetic number, because the mean of its divisors is an integer number (464697000).

Almost surely, 2^21097319320 is an apocalyptic number.

21097319320 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 21097319320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29740608000).

21097319320 is an abundant number, since it is smaller than the sum of its proper divisors (38383896680).

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

21097319320 is a wasteful number, since it uses less digits than its factorization.

21097319320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34649 (or 34645 counting only the distinct ones).

The product of its (nonzero) digits is 20412, while the sum is 37.

The spelling of 21097319320 in words is "twenty-one billion, ninety-seven million, three hundred nineteen thousand, three hundred twenty".