31984240 has 40 divisors (see below), whose sum is σ = 74825568. Its totient is φ = 12714240.

The previous prime is 31984229. The next prime is 31984241. The reversal of 31984240 is 4248913.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31984241) 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, 12685 + ... + 14995.

Almost surely, 2^31984240 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 31984240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37412784).

31984240 is an abundant number, since it is smaller than the sum of its proper divisors (42841328).

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

31984240 is a wasteful number, since it uses less digits than its factorization.

31984240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2497 (or 2491 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 31984240 is about 5655.4610775780. The cubic root of 31984240 is about 317.4280821671.

The spelling of 31984240 in words is "thirty-one million, nine hundred eighty-four thousand, two hundred forty".