857405 has 4 divisors (see below), whose sum is σ = 1028892. Its totient is φ = 685920.

The previous prime is 857369. The next prime is 857407. The reversal of 857405 is 504758.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 375769 + 481636 = 613^2 + 694^2 .

It is not a de Polignac number, because 857405 - 2⁶ = 857341 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85736 + ... + 85745.

It is an arithmetic number, because the mean of its divisors is an integer number (257223).

2⁸⁵⁷⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

857405 is a deficient number, since it is larger than the sum of its proper divisors (171487).

857405 is a wasteful number, since it uses less digits than its factorization.

857405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171486.

The product of its (nonzero) digits is 5600, while the sum is 29.

The square root of 857405 is about 925.9616622733. The cubic root of 857405 is about 95.0011080203.

The spelling of 857405 in words is "eight hundred fifty-seven thousand, four hundred five".