851409 has 24 divisors (see below), whose sum is σ = 1397760. Its totient is φ = 495072.

The previous prime is 851401. The next prime is 851413. The reversal of 851409 is 904158.

It is not a de Polignac number, because 851409 - 2³ = 851401 is a prime.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 851409.

It is not an unprimeable number, because it can be changed into a prime (851401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2032 + ... + 2414.

It is an arithmetic number, because the mean of its divisors is an integer number (58240).

2⁸⁵¹⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

851409 is a deficient number, since it is larger than the sum of its proper divisors (546351).

851409 is a wasteful number, since it uses less digits than its factorization.

851409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421 (or 418 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 851409 is about 922.7182668616. The cubic root of 851409 is about 94.7791360377.

The spelling of 851409 in words is "eight hundred fifty-one thousand, four hundred nine".