816691 has 2 divisors, whose sum is σ = 816692. Its totient is φ = 816690.

The previous prime is 816689. The next prime is 816703. The reversal of 816691 is 196618.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 816691 - 2¹ = 816689 is a prime.

Together with 816689, it forms a pair of twin primes.

It is a Chen prime.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (816091) 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, 408345 + 408346.

It is an arithmetic number, because the mean of its divisors is an integer number (408346).

2⁸¹⁶⁶⁹¹ is an apocalyptic number.

816691 is a deficient number, since it is larger than the sum of its proper divisors (1).

816691 is an equidigital number, since it uses as much as digits as its factorization.

816691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 816691 is about 903.7095772426. The cubic root of 816691 is about 93.4729444057.

The spelling of 816691 in words is "eight hundred sixteen thousand, six hundred ninety-one".