21331231994 has 16 divisors (see below), whose sum is σ = 32059989000. Its totient is φ = 10644588864.

The previous prime is 21331231981. The next prime is 21331231997. The reversal of 21331231994 is 49913213312.

It can be written as a sum of positive squares in 4 ways, for example, as 20488200769 + 843031225 = 143137^2 + 29035^2 .

It is not an unprimeable number, because it can be changed into a prime (21331231997) 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, 2947172 + ... + 2954400.

Almost surely, 2^21331231994 is an apocalyptic number.

21331231994 is a deficient number, since it is larger than the sum of its proper divisors (10728757006).

21331231994 is a wasteful number, since it uses less digits than its factorization.

21331231994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9937.

The product of its digits is 34992, while the sum is 38.

The spelling of 21331231994 in words is "twenty-one billion, three hundred thirty-one million, two hundred thirty-one thousand, nine hundred ninety-four".