31981842 has 24 divisors (see below), whose sum is σ = 69741516. Its totient is φ = 10591776.

The previous prime is 31981823. The next prime is 31981849. The reversal of 31981842 is 24818913.

It can be written as a sum of positive squares in 2 ways, for example, as 30702681 + 1279161 = 5541^2 + 1131^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31981797 and 31981806.

It is not an unprimeable number, because it can be changed into a prime (31981849) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2833 + ... + 8484.

Almost surely, 2^31981842 is an apocalyptic number.

31981842 is an abundant number, since it is smaller than the sum of its proper divisors (37759674).

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

31981842 is a wasteful number, since it uses less digits than its factorization.

31981842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11482 (or 11479 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 31981842 is about 5655.2490661332. The cubic root of 31981842 is about 317.4201489729.

It can be divided in two parts, 31981 and 842, that added together give a palindrome (32823).

The spelling of 31981842 in words is "thirty-one million, nine hundred eighty-one thousand, eight hundred forty-two".