31991497 has 8 divisors (see below), whose sum is σ = 33728000. Its totient is φ = 30260304.

The previous prime is 31991483. The next prime is 31991503. The reversal of 31991497 is 79419913.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31991497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31991797) 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, 19879 + ... + 21427.

It is an arithmetic number, because the mean of its divisors is an integer number (4216000).

Almost surely, 2^31991497 is an apocalyptic number.

It is an amenable number.

31991497 is a deficient number, since it is larger than the sum of its proper divisors (1736503).

31991497 is a wasteful number, since it uses less digits than its factorization.

31991497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2655.

The product of its digits is 61236, while the sum is 43.

The square root of 31991497 is about 5656.1026334394. The cubic root of 31991497 is about 317.4520877544.

The spelling of 31991497 in words is "thirty-one million, nine hundred ninety-one thousand, four hundred ninety-seven".