31401640720 has 20 divisors (see below), whose sum is σ = 73008814860. Its totient is φ = 12560656256.

The previous prime is 31401640657. The next prime is 31401640733. The reversal of 31401640720 is 2704610413.

It can be written as a sum of positive squares in 2 ways, for example, as 18427519504 + 12974121216 = 135748^2 + 113904^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 196260175 + ... + 196260334.

It is an arithmetic number, because the mean of its divisors is an integer number (3650440743).

Almost surely, 2^31401640720 is an apocalyptic number.

It is an amenable number.

31401640720 is an abundant number, since it is smaller than the sum of its proper divisors (41607174140).

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

31401640720 is a wasteful number, since it uses less digits than its factorization.

31401640720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392520522 (or 392520516 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The spelling of 31401640720 in words is "thirty-one billion, four hundred one million, six hundred forty thousand, seven hundred twenty".