31686905440 has 96 divisors (see below), whose sum is σ = 77340082176. Its totient is φ = 12255598080.

The previous prime is 31686905431. The next prime is 31686905447. The reversal of 31686905440 is 4450968613.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31686905447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8841889 + ... + 8845471.

It is an arithmetic number, because the mean of its divisors is an integer number (805625856).

Almost surely, 2^31686905440 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 31686905440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38670041088).

31686905440 is an abundant number, since it is smaller than the sum of its proper divisors (45653176736).

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

31686905440 is a wasteful number, since it uses less digits than its factorization.

31686905440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5412 (or 5404 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 46.

The spelling of 31686905440 in words is "thirty-one billion, six hundred eighty-six million, nine hundred five thousand, four hundred forty".