31981140 has 72 divisors (see below), whose sum is σ = 97843200. Its totient is φ = 8455104.

The previous prime is 31981133. The next prime is 31981193. The reversal of 31981140 is 4118913.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22161 + ... + 23559.

Almost surely, 2^31981140 is an apocalyptic number.

31981140 is a gapful number since it is divisible by the number (30) 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 31981140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48921600).

31981140 is an abundant number, since it is smaller than the sum of its proper divisors (65862060).

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

31981140 is a wasteful number, since it uses less digits than its factorization.

31981140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1541 (or 1536 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 31981140 is about 5655.1869995607. The cubic root of 31981140 is about 317.4178265032.

The spelling of 31981140 in words is "thirty-one million, nine hundred eighty-one thousand, one hundred forty".