858409 has 4 divisors (see below), whose sum is σ = 878416. Its totient is φ = 838404.

The previous prime is 858397. The next prime is 858427. The reversal of 858409 is 904858.

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 858409 - 2⁷ = 858281 is a prime.

It is a super-2 number, since 2×858409² = 1473732022562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (858479) 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, 9939 + ... + 10024.

It is an arithmetic number, because the mean of its divisors is an integer number (219604).

2⁸⁵⁸⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

858409 is a deficient number, since it is larger than the sum of its proper divisors (20007).

858409 is a wasteful number, since it uses less digits than its factorization.

858409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20006.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 858409 is about 926.5036427343. The cubic root of 858409 is about 95.0381748701.

It can be divided in two parts, 85840 and 9, that added together give a square (85849 = 293²).

The spelling of 858409 in words is "eight hundred fifty-eight thousand, four hundred nine".