31531304440 has 128 divisors (see below), whose sum is σ = 76732790400. Its totient is φ = 11625349120.

The previous prime is 31531304437. The next prime is 31531304447. The reversal of 31531304440 is 4440313513.

It is a junction number, because it is equal to n+sod(n) for n = 31531304399 and 31531304408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31531304447) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20302704 + ... + 20304256.

It is an arithmetic number, because the mean of its divisors is an integer number (599474925).

Almost surely, 2^31531304440 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 31531304440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38366395200).

31531304440 is an abundant number, since it is smaller than the sum of its proper divisors (45201485960).

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

31531304440 is a wasteful number, since it uses less digits than its factorization.

31531304440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2377 (or 2373 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 28.

Adding to 31531304440 its reverse (4440313513), we get a palindrome (35971617953).

The spelling of 31531304440 in words is "thirty-one billion, five hundred thirty-one million, three hundred four thousand, four hundred forty".