21131331320 has 32 divisors (see below), whose sum is σ = 51867814320. Its totient is φ = 7684120320.

The previous prime is 21131331317. The next prime is 21131331323. The reversal of 21131331320 is 2313313112.

It is an interprime number because it is at equal distance from previous prime (21131331317) and next prime (21131331323).

It is a super-2 number, since 2×21131331320² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21131331292 and 21131331301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131331323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24012437 + ... + 24013316.

Almost surely, 2^21131331320 is an apocalyptic number.

21131331320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21131331320 is an abundant number, since it is smaller than the sum of its proper divisors (30736483000).

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

21131331320 is a wasteful number, since it uses less digits than its factorization.

21131331320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48025775 (or 48025771 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 21131331320 its reverse (2313313112), we get a palindrome (23444644432).

The spelling of 21131331320 in words is "twenty-one billion, one hundred thirty-one million, three hundred thirty-one thousand, three hundred twenty".