31997999 has 8 divisors (see below), whose sum is σ = 35758800. Its totient is φ = 28379200.

The previous prime is 31997989. The next prime is 31998073. The reversal of 31997999 is 99979913.

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-31997999 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31997909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35024 + ... + 35925.

It is an arithmetic number, because the mean of its divisors is an integer number (4469850).

Almost surely, 2^31997999 is an apocalyptic number.

31997999 is a deficient number, since it is larger than the sum of its proper divisors (3760801).

31997999 is a wasteful number, since it uses less digits than its factorization.

31997999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71001.

The product of its digits is 1240029, while the sum is 56.

The square root of 31997999 is about 5656.6773816438. The cubic root of 31997999 is about 317.4735927776.

The spelling of 31997999 in words is "thirty-one million, nine hundred ninety-seven thousand, nine hundred ninety-nine".