21331210320 has 480 divisors, whose sum is σ = 86566721280. Its totient is φ = 4598415360.

The previous prime is 21331210259. The next prime is 21331210399. The reversal of 21331210320 is 2301213312.

21331210320 is a `hidden beast` number, since 2 + 1 + 331 + 2 + 10 + 320 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21331210293 and 21331210302.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 32270790 + ... + 32271450.

It is an arithmetic number, because the mean of its divisors is an integer number (180347336).

Almost surely, 2^21331210320 is an apocalyptic number.

21331210320 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 21331210320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43283360640).

21331210320 is an abundant number, since it is smaller than the sum of its proper divisors (65235510960).

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

21331210320 is a wasteful number, since it uses less digits than its factorization.

21331210320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1043 (or 1034 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 21331210320 its reverse (2301213312), we get a palindrome (23632423632).

The spelling of 21331210320 in words is "twenty-one billion, three hundred thirty-one million, two hundred ten thousand, three hundred twenty".