21131331072 has 160 divisors (see below), whose sum is σ = 59168093952. Its totient is φ = 6693249024.

The previous prime is 21131330963. The next prime is 21131331073. The reversal of 21131331072 is 27013313112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131331073) 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 15 ways as a sum of consecutive naturals, for example, 2439453 + ... + 2448099.

Almost surely, 2^21131331072 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21131331072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29584046976).

21131331072 is an abundant number, since it is smaller than the sum of its proper divisors (38036762880).

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

21131331072 is an equidigital number, since it uses as much as digits as its factorization.

21131331072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8748 (or 8732 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 24.

Adding to 21131331072 its reverse (27013313112), we get a palindrome (48144644184).

The spelling of 21131331072 in words is "twenty-one billion, one hundred thirty-one million, three hundred thirty-one thousand, seventy-two".