842405 has 4 divisors (see below), whose sum is σ = 1010892. Its totient is φ = 673920.

The previous prime is 842399. The next prime is 842407. The reversal of 842405 is 504248.

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 388129 + 454276 = 623^2 + 674^2 .

It is not a de Polignac number, because 842405 - 2⁶ = 842341 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 842405.

It is not an unprimeable number, because it can be changed into a prime (842407) 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, 84236 + ... + 84245.

It is an arithmetic number, because the mean of its divisors is an integer number (252723).

2⁸⁴²⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

842405 is a deficient number, since it is larger than the sum of its proper divisors (168487).

842405 is a wasteful number, since it uses less digits than its factorization.

842405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168486.

The product of its (nonzero) digits is 1280, while the sum is 23.

The square root of 842405 is about 917.8262362779. The cubic root of 842405 is about 94.4438418519.

The spelling of 842405 in words is "eight hundred forty-two thousand, four hundred five".