820125857 has 2 divisors, whose sum is σ = 820125858. Its totient is φ = 820125856.

The previous prime is 820125853. The next prime is 820125931. The reversal of 820125857 is 758521028.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 709476496 + 110649361 = 26636^2 + 10519^2 .

It is a cyclic number.

It is not a de Polignac number, because 820125857 - 2² = 820125853 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 820125857.

It is not a weakly prime, because it can be changed into another prime (820125853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410062928 + 410062929.

It is an arithmetic number, because the mean of its divisors is an integer number (410062929).

Almost surely, 2^820125857 is an apocalyptic number.

It is an amenable number.

820125857 is a deficient number, since it is larger than the sum of its proper divisors (1).

820125857 is an equidigital number, since it uses as much as digits as its factorization.

820125857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 44800, while the sum is 38.

The square root of 820125857 is about 28637.8396007799. The cubic root of 820125857 is about 936.0380464147.

The spelling of 820125857 in words is "eight hundred twenty million, one hundred twenty-five thousand, eight hundred fifty-seven".