31230991 has 16 divisors (see below), whose sum is σ = 34997760. Its totient is φ = 27630720.

The previous prime is 31230977. The next prime is 31231009. The reversal of 31230991 is 19903213.

It is a cyclic number.

It is not a de Polignac number, because 31230991 - 2⁵ = 31230959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31230961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71911 + ... + 72343.

It is an arithmetic number, because the mean of its divisors is an integer number (2187360).

Almost surely, 2^31230991 is an apocalyptic number.

31230991 is a deficient number, since it is larger than the sum of its proper divisors (3766769).

31230991 is a wasteful number, since it uses less digits than its factorization.

31230991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 31230991 is about 5588.4694684681. The cubic root of 31230991 is about 314.9163832817.

The spelling of 31230991 in words is "thirty-one million, two hundred thirty thousand, nine hundred ninety-one".