31131533440 has 256 divisors, whose sum is σ = 89835724800. Its totient is φ = 10077696000.

The previous prime is 31131533393. The next prime is 31131533443. The reversal of 31131533440 is 4433513113.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 31131533399 and 31131533408.

It is not an unprimeable number, because it can be changed into a prime (31131533443) 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, 41453065 + ... + 41453815.

It is an arithmetic number, because the mean of its divisors is an integer number (350920800).

Almost surely, 2^31131533440 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 31131533440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44917862400).

31131533440 is an abundant number, since it is smaller than the sum of its proper divisors (58704191360).

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

31131533440 is a wasteful number, since it uses less digits than its factorization.

31131533440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1283 (or 1271 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 28.

The spelling of 31131533440 in words is "thirty-one billion, one hundred thirty-one million, five hundred thirty-three thousand, four hundred forty".