857521 has 4 divisors (see below), whose sum is σ = 980032. Its totient is φ = 735012.

The previous prime is 857513. The next prime is 857539. The reversal of 857521 is 125758.

857521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 857521 - 2³ = 857513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 857521.

It is not an unprimeable number, because it can be changed into a prime (857551) 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, 61245 + ... + 61258.

It is an arithmetic number, because the mean of its divisors is an integer number (245008).

2⁸⁵⁷⁵²¹ is an apocalyptic number.

It is an amenable number.

857521 is a deficient number, since it is larger than the sum of its proper divisors (122511).

857521 is a wasteful number, since it uses less digits than its factorization.

857521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122510.

The product of its digits is 2800, while the sum is 28.

The square root of 857521 is about 926.0242977374. The cubic root of 857521 is about 95.0053921224.

It can be divided in two parts, 857 and 521, that added together give a triangular number (1378 = T₅₂).

The spelling of 857521 in words is "eight hundred fifty-seven thousand, five hundred twenty-one".