820920817 has 2 divisors, whose sum is σ = 820920818. Its totient is φ = 820920816.

The previous prime is 820920791. The next prime is 820920823. The reversal of 820920817 is 718029028.

820920817 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 818017201 + 2903616 = 28601^2 + 1704^2 .

It is a cyclic number.

It is not a de Polignac number, because 820920817 - 2²⁷ = 686703089 is a prime.

It is not a weakly prime, because it can be changed into another prime (820920857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410460408 + 410460409.

It is an arithmetic number, because the mean of its divisors is an integer number (410460409).

Almost surely, 2^820920817 is an apocalyptic number.

It is an amenable number.

820920817 is a deficient number, since it is larger than the sum of its proper divisors (1).

820920817 is an equidigital number, since it uses as much as digits as its factorization.

820920817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 820920817 is about 28651.7157775935. The cubic root of 820920817 is about 936.3403872087.

The spelling of 820920817 in words is "eight hundred twenty million, nine hundred twenty thousand, eight hundred seventeen".