31397665908 has 144 divisors (see below), whose sum is σ = 94985110080. Its totient is φ = 7998649344.

The previous prime is 31397665903. The next prime is 31397665919. The reversal of 31397665908 is 80956679313.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31397665903) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 107266 + ... + 272582.

It is an arithmetic number, because the mean of its divisors is an integer number (659618820).

Almost surely, 2^31397665908 is an apocalyptic number.

31397665908 is a gapful number since it is divisible by the number (38) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31397665908, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47492555040).

31397665908 is an abundant number, since it is smaller than the sum of its proper divisors (63587444172).

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

31397665908 is a wasteful number, since it uses less digits than its factorization.

31397665908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165374 (or 165365 counting only the distinct ones).

The product of its (nonzero) digits is 7348320, while the sum is 57.

The spelling of 31397665908 in words is "thirty-one billion, three hundred ninety-seven million, six hundred sixty-five thousand, nine hundred eight".