21313021320 has 160 divisors (see below), whose sum is σ = 72543081600. Its totient is φ = 5611462272.

The previous prime is 21313021283. The next prime is 21313021339. The reversal of 21313021320 is 2312031312.

21313021320 is a `hidden beast` number, since 213 + 130 + 2 + 1 + 320 = 666.

It is a super-3 number, since 3×21313021320³ (a number of 32 digits) contains 333 as substring.

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 = 21313021293 and 21313021302.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 214327 + ... + 297593.

It is an arithmetic number, because the mean of its divisors is an integer number (453394260).

Almost surely, 2^21313021320 is an apocalyptic number.

21313021320 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 21313021320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36271540800).

21313021320 is an abundant number, since it is smaller than the sum of its proper divisors (51230060280).

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

21313021320 is a wasteful number, since it uses less digits than its factorization.

21313021320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83369 (or 83356 counting only the distinct ones).

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

Adding to 21313021320 its reverse (2312031312), we get a palindrome (23625052632).

The spelling of 21313021320 in words is "twenty-one billion, three hundred thirteen million, twenty-one thousand, three hundred twenty".