9991123 has 2 divisors, whose sum is σ = 9991124. Its totient is φ = 9991122.

The previous prime is 9991067. The next prime is 9991127. The reversal of 9991123 is 3211999.

9991123 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9991123 is a prime.

It is a super-2 number, since 2×9991123² = 199645077602258, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (9991127) 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 as a sum of consecutive naturals, namely, 4995561 + 4995562.

It is an arithmetic number, because the mean of its divisors is an integer number (4995562).

Almost surely, 2^9991123 is an apocalyptic number.

9991123 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991123 is an equidigital number, since it uses as much as digits as its factorization.

9991123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4374, while the sum is 34.

The square root of 9991123 is about 3160.8737716018. The cubic root of 9991123 is about 215.3797004079.

The spelling of 9991123 in words is "nine million, nine hundred ninety-one thousand, one hundred twenty-three".