691799 has 2 divisors, whose sum is σ = 691800. Its totient is φ = 691798.

The previous prime is 691787. The next prime is 691813. The reversal of 691799 is 997196.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691709) 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 as a sum of consecutive naturals, namely, 345899 + 345900.

It is an arithmetic number, because the mean of its divisors is an integer number (345900).

2⁶⁹¹⁷⁹⁹ is an apocalyptic number.

691799 is a deficient number, since it is larger than the sum of its proper divisors (1).

691799 is an equidigital number, since it uses as much as digits as its factorization.

691799 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30618, while the sum is 41.

The square root of 691799 is about 831.7445521312. The cubic root of 691799 is about 88.4422895057.

The spelling of 691799 in words is "six hundred ninety-one thousand, seven hundred ninety-nine".