991744231 has 2 divisors, whose sum is σ = 991744232. Its totient is φ = 991744230.

The previous prime is 991744223. The next prime is 991744261. The reversal of 991744231 is 132447199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991744231 - 2³ = 991744223 is a prime.

It is a super-2 number, since 2×991744231² = 1967113239443562722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991744211) 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 as a sum of consecutive naturals, namely, 495872115 + 495872116.

It is an arithmetic number, because the mean of its divisors is an integer number (495872116).

Almost surely, 2^991744231 is an apocalyptic number.

991744231 is a deficient number, since it is larger than the sum of its proper divisors (1).

991744231 is an equidigital number, since it uses as much as digits as its factorization.

991744231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 40.

The square root of 991744231 is about 31491.9708973573. The cubic root of 991744231 is about 997.2404689932.

The spelling of 991744231 in words is "nine hundred ninety-one million, seven hundred forty-four thousand, two hundred thirty-one".