842409 has 6 divisors (see below), whose sum is σ = 1216826. Its totient is φ = 561600.

The previous prime is 842407. The next prime is 842417. The reversal of 842409 is 904248.

It can be written as a sum of positive squares in only one way, i.e., 837225 + 5184 = 915^2 + 72^2 .

It is not a de Polignac number, because 842409 - 2¹ = 842407 is a prime.

It is a Duffinian number.

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 5 ways as a sum of consecutive naturals, for example, 46792 + ... + 46809.

2⁸⁴²⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

842409 is a deficient number, since it is larger than the sum of its proper divisors (374417).

842409 is a wasteful number, since it uses less digits than its factorization.

842409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93607 (or 93604 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 842409 is about 917.8284153370. The cubic root of 842409 is about 94.4439913345.

The spelling of 842409 in words is "eight hundred forty-two thousand, four hundred nine".