31505412640 has 144 divisors (see below), whose sum is σ = 81028486728. Its totient is φ = 11570577408.

The previous prime is 31505412611. The next prime is 31505412641. The reversal of 31505412640 is 4621450513.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 4064827536 + 27440585104 = 63756^2 + 165652^2 .

It is not an unprimeable number, because it can be changed into a prime (31505412641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5215702 + ... + 5221738.

Almost surely, 2^31505412640 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 31505412640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40514243364).

31505412640 is an abundant number, since it is smaller than the sum of its proper divisors (49523074088).

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

31505412640 is a wasteful number, since it uses less digits than its factorization.

31505412640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6271 (or 6250 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 31.

The spelling of 31505412640 in words is "thirty-one billion, five hundred five million, four hundred twelve thousand, six hundred forty".