820657 has 2 divisors, whose sum is σ = 820658. Its totient is φ = 820656.

The previous prime is 820649. The next prime is 820679. The reversal of 820657 is 756028.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 720801 + 99856 = 849^2 + 316^2 .

It is a cyclic number.

It is not a de Polignac number, because 820657 - 2³ = 820649 is a prime.

It is equal to p₆₅₄₆₇ and since 820657 and 65467 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (820627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410328 + 410329.

It is an arithmetic number, because the mean of its divisors is an integer number (410329).

2⁸²⁰⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

820657 is a deficient number, since it is larger than the sum of its proper divisors (1).

820657 is an equidigital number, since it uses as much as digits as its factorization.

820657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 820657 is about 905.9012087419. The cubic root of 820657 is about 93.6240073442.

The spelling of 820657 in words is "eight hundred twenty thousand, six hundred fifty-seven".