31987120 has 80 divisors (see below), whose sum is σ = 81994752. Its totient is φ = 11508480.

The previous prime is 31987117. The next prime is 31987139. The reversal of 31987120 is 2178913.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 143329 + ... + 143551.

Almost surely, 2^31987120 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 31987120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40997376).

31987120 is an abundant number, since it is smaller than the sum of its proper divisors (50007632).

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

31987120 is a wasteful number, since it uses less digits than its factorization.

31987120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410 (or 404 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 31987120 is about 5655.7156929959. The cubic root of 31987120 is about 317.4376094159.

The spelling of 31987120 in words is "thirty-one million, nine hundred eighty-seven thousand, one hundred twenty".