691105399 has 2 divisors, whose sum is σ = 691105400. Its totient is φ = 691105398.

The previous prime is 691105397. The next prime is 691105433. The reversal of 691105399 is 993501196.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691105399 - 2¹ = 691105397 is a prime.

Together with 691105397, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691105397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345552699 + 345552700.

It is an arithmetic number, because the mean of its divisors is an integer number (345552700).

Almost surely, 2^691105399 is an apocalyptic number.

691105399 is a deficient number, since it is larger than the sum of its proper divisors (1).

691105399 is an equidigital number, since it uses as much as digits as its factorization.

691105399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 65610, while the sum is 43.

The square root of 691105399 is about 26288.8835632098. The cubic root of 691105399 is about 884.1272206731.

The spelling of 691105399 in words is "six hundred ninety-one million, one hundred five thousand, three hundred ninety-nine".