31373991 has 24 divisors (see below), whose sum is σ = 49645440. Its totient is φ = 18934800.

The previous prime is 31373989. The next prime is 31374011. The reversal of 31373991 is 19937313.

It is not a de Polignac number, because 31373991 - 2¹ = 31373989 is a prime.

It is a super-2 number, since 2×31373991² = 1968654622536162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31373591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30280 + ... + 31298.

It is an arithmetic number, because the mean of its divisors is an integer number (2068560).

Almost surely, 2^31373991 is an apocalyptic number.

31373991 is a deficient number, since it is larger than the sum of its proper divisors (18271449).

31373991 is a wasteful number, since it uses less digits than its factorization.

31373991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1347 (or 1344 counting only the distinct ones).

The product of its digits is 15309, while the sum is 36.

The square root of 31373991 is about 5601.2490571300. The cubic root of 31373991 is about 315.3962963794.

The spelling of 31373991 in words is "thirty-one million, three hundred seventy-three thousand, nine hundred ninety-one".