109081991 has 2 divisors, whose sum is σ = 109081992. Its totient is φ = 109081990.

The previous prime is 109081961. The next prime is 109082009. The reversal of 109081991 is 199180901.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 109081991 - 2¹⁸ = 108819847 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (109081961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54540995 + 54540996.

It is an arithmetic number, because the mean of its divisors is an integer number (54540996).

Almost surely, 2^109081991 is an apocalyptic number.

109081991 is a deficient number, since it is larger than the sum of its proper divisors (1).

109081991 is an equidigital number, since it uses as much as digits as its factorization.

109081991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 38.

The square root of 109081991 is about 10444.2324275171. The cubic root of 109081991 is about 477.8053615447.

The spelling of 109081991 in words is "one hundred nine million, eighty-one thousand, nine hundred ninety-one".