810857 has 4 divisors (see below), whose sum is σ = 830676. Its totient is φ = 791040.

The previous prime is 810853. The next prime is 810871. The reversal of 810857 is 758018.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 758018 = 2 ⋅379009.

It can be written as a sum of positive squares in 2 ways, for example, as 177241 + 633616 = 421^2 + 796^2 .

It is a cyclic number.

It is not a de Polignac number, because 810857 - 2² = 810853 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (810853) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9848 + ... + 9929.

It is an arithmetic number, because the mean of its divisors is an integer number (207669).

2⁸¹⁰⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

810857 is a deficient number, since it is larger than the sum of its proper divisors (19819).

810857 is a wasteful number, since it uses less digits than its factorization.

810857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19818.

The product of its (nonzero) digits is 2240, while the sum is 29.

The square root of 810857 is about 900.4759852434. The cubic root of 810857 is about 93.2498388783.

The spelling of 810857 in words is "eight hundred ten thousand, eight hundred fifty-seven".