31997740 has 24 divisors (see below), whose sum is σ = 71148672. Its totient is φ = 12046080.

The previous prime is 31997737. The next prime is 31997747. The reversal of 31997740 is 4779913.

It is a junction number, because it is equal to n+sod(n) for n = 31997693 and 31997702.

It is not an unprimeable number, because it can be changed into a prime (31997747) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46716 + ... + 47395.

It is an arithmetic number, because the mean of its divisors is an integer number (2964528).

Almost surely, 2^31997740 is an apocalyptic number.

It is an amenable number.

31997740 is an abundant number, since it is smaller than the sum of its proper divisors (39150932).

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

31997740 is a wasteful number, since it uses less digits than its factorization.

31997740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94137 (or 94135 counting only the distinct ones).

The product of its (nonzero) digits is 47628, while the sum is 40.

The square root of 31997740 is about 5656.6544882996. The cubic root of 31997740 is about 317.4727362044.

The spelling of 31997740 in words is "thirty-one million, nine hundred ninety-seven thousand, seven hundred forty".