857121 has 4 divisors (see below), whose sum is σ = 1142832. Its totient is φ = 571412.

The previous prime is 857107. The next prime is 857137. The reversal of 857121 is 121758.

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 857121 - 2⁷ = 856993 is a prime.

It is a D-number.

It is a junction number, because it is equal to n+sod(n) for n = 857091 and 857100.

It is not an unprimeable number, because it can be changed into a prime (857161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142851 + ... + 142856.

It is an arithmetic number, because the mean of its divisors is an integer number (285708).

2⁸⁵⁷¹²¹ is an apocalyptic number.

It is an amenable number.

857121 is a deficient number, since it is larger than the sum of its proper divisors (285711).

857121 is a wasteful number, since it uses less digits than its factorization.

857121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285710.

The product of its digits is 560, while the sum is 24.

The square root of 857121 is about 925.8082954910. The cubic root of 857121 is about 94.9906177253.

Adding to 857121 its reverse (121758), we get a palindrome (978879).

The spelling of 857121 in words is "eight hundred fifty-seven thousand, one hundred twenty-one".