21320100520 has 128 divisors (see below), whose sum is σ = 53663731200. Its totient is φ = 7584403456.

The previous prime is 21320100511. The next prime is 21320100541. The reversal of 21320100520 is 2500102312.

It is a junction number, because it is equal to n+sod(n) for n = 21320100494 and 21320100503.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 915339 + ... + 938341.

It is an arithmetic number, because the mean of its divisors is an integer number (419247900).

Almost surely, 2^21320100520 is an apocalyptic number.

21320100520 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 21320100520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26831865600).

21320100520 is an abundant number, since it is smaller than the sum of its proper divisors (32343630680).

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

21320100520 is a wasteful number, since it uses less digits than its factorization.

21320100520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23107 (or 23103 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

Adding to 21320100520 its reverse (2500102312), we get a palindrome (23820202832).

The spelling of 21320100520 in words is "twenty-one billion, three hundred twenty million, one hundred thousand, five hundred twenty".