991109149 has 2 divisors, whose sum is σ = 991109150. Its totient is φ = 991109148.

The previous prime is 991109089. The next prime is 991109159. The reversal of 991109149 is 941901199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 801909124 + 189200025 = 28318^2 + 13755^2 .

It is a cyclic number.

It is not a de Polignac number, because 991109149 - 2²⁷ = 856891421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991109159) 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, 495554574 + 495554575.

It is an arithmetic number, because the mean of its divisors is an integer number (495554575).

Almost surely, 2^991109149 is an apocalyptic number.

It is an amenable number.

991109149 is a deficient number, since it is larger than the sum of its proper divisors (1).

991109149 is an equidigital number, since it uses as much as digits as its factorization.

991109149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26244, while the sum is 43.

The square root of 991109149 is about 31481.8860457883. The cubic root of 991109149 is about 997.0275563329.

The spelling of 991109149 in words is "nine hundred ninety-one million, one hundred nine thousand, one hundred forty-nine".