12991109 has 4 divisors (see below), whose sum is σ = 13204140. Its totient is φ = 12778080.

The previous prime is 12991103. The next prime is 12991127. The reversal of 12991109 is 90119921.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6630625 + 6360484 = 2575^2 + 2522^2 .

It is a cyclic number.

It is not a de Polignac number, because 12991109 - 2⁸ = 12990853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12991103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106424 + ... + 106545.

It is an arithmetic number, because the mean of its divisors is an integer number (3301035).

Almost surely, 2^12991109 is an apocalyptic number.

It is an amenable number.

12991109 is a deficient number, since it is larger than the sum of its proper divisors (213031).

12991109 is an equidigital number, since it uses as much as digits as its factorization.

12991109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213030.

The product of its (nonzero) digits is 1458, while the sum is 32.

The square root of 12991109 is about 3604.3181047183. The cubic root of 12991109 is about 235.0798521452.

The spelling of 12991109 in words is "twelve million, nine hundred ninety-one thousand, one hundred nine".