691109 has 2 divisors, whose sum is σ = 691110. Its totient is φ = 691108.

The previous prime is 691079. The next prime is 691111. The reversal of 691109 is 901196.

691109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 688900 + 2209 = 830^2 + 47^2 .

It is a cyclic number.

It is not a de Polignac number, because 691109 - 2¹² = 687013 is a prime.

Together with 691111, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691109.

It is not a weakly prime, because it can be changed into another prime (691129) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345554 + 345555.

It is an arithmetic number, because the mean of its divisors is an integer number (345555).

2⁶⁹¹¹⁰⁹ is an apocalyptic number.

It is an amenable number.

691109 is a deficient number, since it is larger than the sum of its proper divisors (1).

691109 is an equidigital number, since it uses as much as digits as its factorization.

691109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 691109 is about 831.3296578374. The cubic root of 691109 is about 88.4128756250.

The spelling of 691109 in words is "six hundred ninety-one thousand, one hundred nine".