31531134440 has 96 divisors (see below), whose sum is σ = 77215378680. Its totient is φ = 11582678016.

The previous prime is 31531134433. The next prime is 31531134491. The reversal of 31531134440 is 4443113513.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 1268356996 + 30262777444 = 35614^2 + 173962^2 .

It is a super-2 number, since 2×31531134440² (a number of 22 digits) contains 22 as substring.

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, 1319882 + ... + 1343558.

Almost surely, 2^31531134440 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 31531134440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38607689340).

31531134440 is an abundant number, since it is smaller than the sum of its proper divisors (45684244240).

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

31531134440 is a wasteful number, since it uses less digits than its factorization.

31531134440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23911 (or 23894 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

Adding to 31531134440 its reverse (4443113513), we get a palindrome (35974247953).

The spelling of 31531134440 in words is "thirty-one billion, five hundred thirty-one million, one hundred thirty-four thousand, four hundred forty".