991109243 has 2 divisors, whose sum is σ = 991109244. Its totient is φ = 991109242.

The previous prime is 991109227. The next prime is 991109267. The reversal of 991109243 is 342901199.

991109243 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991109243 - 2⁴ = 991109227 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 991109197 and 991109206.

It is not a weakly prime, because it can be changed into another prime (991109543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495554621 + 495554622.

It is an arithmetic number, because the mean of its divisors is an integer number (495554622).

Almost surely, 2^991109243 is an apocalyptic number.

991109243 is a deficient number, since it is larger than the sum of its proper divisors (1).

991109243 is an equidigital number, since it uses as much as digits as its factorization.

991109243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 991109243 is about 31481.8875387103. The cubic root of 991109243 is about 997.0275878533.

The spelling of 991109243 in words is "nine hundred ninety-one million, one hundred nine thousand, two hundred forty-three".