991127 has 2 divisors, whose sum is σ = 991128. Its totient is φ = 991126.

The previous prime is 991091. The next prime is 991129. The reversal of 991127 is 721199.

It is a strong prime.

It is an emirp because it is prime and its reverse (721199) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 991127 - 2⁶ = 991063 is a prime.

Together with 991129, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 991127.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495563 + 495564.

It is an arithmetic number, because the mean of its divisors is an integer number (495564).

2⁹⁹¹¹²⁷ is an apocalyptic number.

991127 is a deficient number, since it is larger than the sum of its proper divisors (1).

991127 is an equidigital number, since it uses as much as digits as its factorization.

991127 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1134, while the sum is 29.

The square root of 991127 is about 995.5536148295. The cubic root of 991127 is about 99.7033542163.

The spelling of 991127 in words is "nine hundred ninety-one thousand, one hundred twenty-seven".