31291640928 has 96 divisors (see below), whose sum is σ = 91964315520. Its totient is φ = 10350887040.

The previous prime is 31291640923. The next prime is 31291640951. The reversal of 31291640928 is 82904619213.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31291640923) 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, 25050 + ... + 251417.

It is an arithmetic number, because the mean of its divisors is an integer number (957961620).

Almost surely, 2^31291640928 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 31291640928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45982157760).

31291640928 is an abundant number, since it is smaller than the sum of its proper divisors (60672674592).

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

31291640928 is a wasteful number, since it uses less digits than its factorization.

31291640928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276617 (or 276603 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The spelling of 31291640928 in words is "thirty-one billion, two hundred ninety-one million, six hundred forty thousand, nine hundred twenty-eight".