21313393920 has 1008 divisors, whose sum is σ = 94582518912. Its totient is φ = 4478976000.

The previous prime is 21313393883. The next prime is 21313393921. The reversal of 21313393920 is 2939331312.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (1008).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313393921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 84913795 + ... + 84914045.

It is an arithmetic number, because the mean of its divisors is an integer number (93831864).

Almost surely, 2^21313393920 is an apocalyptic number.

21313393920 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 21313393920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47291259456).

21313393920 is an abundant number, since it is smaller than the sum of its proper divisors (73269124992).

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

21313393920 is an equidigital number, since it uses as much as digits as its factorization.

21313393920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310 (or 281 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 36.

The spelling of 21313393920 in words is "twenty-one billion, three hundred thirteen million, three hundred ninety-three thousand, nine hundred twenty".