31509980 has 48 divisors (see below), whose sum is σ = 70428960. Its totient is φ = 11808000.

The previous prime is 31509971. The next prime is 31509991. The reversal of 31509980 is 8990513.

It is a self number, because there is not a number n which added to its sum of digits gives 31509980.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37970 + ... + 38790.

It is an arithmetic number, because the mean of its divisors is an integer number (1467270).

Almost surely, 2^31509980 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 31509980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35214480).

31509980 is an abundant number, since it is smaller than the sum of its proper divisors (38918980).

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

31509980 is a wasteful number, since it uses less digits than its factorization.

31509980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 950 (or 948 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 31509980 is about 5613.3750988153. The cubic root of 31509980 is about 315.8513294133.

The spelling of 31509980 in words is "thirty-one million, five hundred nine thousand, nine hundred eighty".