21001313320 has 256 divisors, whose sum is σ = 55738368000. Its totient is φ = 7052313600.

The previous prime is 21001313303. The next prime is 21001313381. The reversal of 21001313320 is 2331310012.

It is a super-2 number, since 2×21001313320² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21001313294 and 21001313303.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 58499301 + ... + 58499659.

It is an arithmetic number, because the mean of its divisors is an integer number (217728000).

Almost surely, 2^21001313320 is an apocalyptic number.

21001313320 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 21001313320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27869184000).

21001313320 is an abundant number, since it is smaller than the sum of its proper divisors (34737054680).

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

21001313320 is a wasteful number, since it uses less digits than its factorization.

21001313320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 624 (or 620 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 16.

Adding to 21001313320 its reverse (2331310012), we get a palindrome (23332623332).

The spelling of 21001313320 in words is "twenty-one billion, one million, three hundred thirteen thousand, three hundred twenty".