820691 has 2 divisors, whose sum is σ = 820692. Its totient is φ = 820690.

The previous prime is 820681. The next prime is 820711. The reversal of 820691 is 196028.

820691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 820691 - 2⁶ = 820627 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 820691.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 820691.

It is not a weakly prime, because it can be changed into another prime (820681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410345 + 410346.

It is an arithmetic number, because the mean of its divisors is an integer number (410346).

2⁸²⁰⁶⁹¹ is an apocalyptic number.

820691 is a deficient number, since it is larger than the sum of its proper divisors (1).

820691 is an equidigital number, since it uses as much as digits as its factorization.

820691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 820691 is about 905.9199743907. The cubic root of 820691 is about 93.6253002807.

The spelling of 820691 in words is "eight hundred twenty thousand, six hundred ninety-one".