857861 has 4 divisors (see below), whose sum is σ = 868800. Its totient is φ = 846924.

The previous prime is 857851. The next prime is 857867. The reversal of 857861 is 168758.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 857861 - 2¹⁸ = 595717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857867) 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, 5351 + ... + 5508.

It is an arithmetic number, because the mean of its divisors is an integer number (217200).

2⁸⁵⁷⁸⁶¹ is an apocalyptic number.

It is an amenable number.

857861 is a deficient number, since it is larger than the sum of its proper divisors (10939).

857861 is a wasteful number, since it uses less digits than its factorization.

857861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10938.

The product of its digits is 13440, while the sum is 35.

The square root of 857861 is about 926.2078600401. The cubic root of 857861 is about 95.0179467479.

The spelling of 857861 in words is "eight hundred fifty-seven thousand, eight hundred sixty-one".