31331691 has 14 divisors (see below), whose sum is σ = 46977140. Its totient is φ = 20887308.

The previous prime is 31331683. The next prime is 31331693. The reversal of 31331691 is 19613313.

It is not a de Polignac number, because 31331691 - 2³ = 31331683 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31331693) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 20761 + ... + 22218.

It is an arithmetic number, because the mean of its divisors is an integer number (3355510).

Almost surely, 2^31331691 is an apocalyptic number.

31331691 is a deficient number, since it is larger than the sum of its proper divisors (15645449).

31331691 is an frugal number, since it uses more digits than its factorization.

31331691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42997 (or 42982 counting only the distinct ones).

The product of its digits is 1458, while the sum is 27.

The square root of 31331691 is about 5597.4718400364. The cubic root of 31331691 is about 315.2544882214.

The spelling of 31331691 in words is "thirty-one million, three hundred thirty-one thousand, six hundred ninety-one".