31989240 has 96 divisors (see below), whose sum is σ = 110101680. Its totient is φ = 8027136.

The previous prime is 31989229. The next prime is 31989259. The reversal of 31989240 is 4298913.

It is a super-2 number, since 2×31989240² = 2046622951555200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 31989195 and 31989204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3507 + ... + 8733.

Almost surely, 2^31989240 is an apocalyptic number.

31989240 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 31989240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55050840).

31989240 is an abundant number, since it is smaller than the sum of its proper divisors (78112440).

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

31989240 is a wasteful number, since it uses less digits than its factorization.

31989240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5261 (or 5254 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 31989240 is about 5655.9031109099. The cubic root of 31989240 is about 317.4446221642. Note that the first 3 decimals are identical.

The spelling of 31989240 in words is "thirty-one million, nine hundred eighty-nine thousand, two hundred forty".