842421 has 16 divisors (see below), whose sum is σ = 1215360. Its totient is φ = 517440.

The previous prime is 842419. The next prime is 842423. The reversal of 842421 is 124248.

It is an interprime number because it is at equal distance from previous prime (842419) and next prime (842423).

It is not a de Polignac number, because 842421 - 2¹ = 842419 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (842423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1791 + ... + 2211.

It is an arithmetic number, because the mean of its divisors is an integer number (75960).

2⁸⁴²⁴²¹ is an apocalyptic number.

It is an amenable number.

842421 is a deficient number, since it is larger than the sum of its proper divisors (372939).

842421 is a wasteful number, since it uses less digits than its factorization.

842421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476.

The product of its digits is 512, while the sum is 21.

The square root of 842421 is about 917.8349524833. The cubic root of 842421 is about 94.4444397796. Note that the first 4 decimals are identical.

Adding to 842421 its reverse (124248), we get a palindrome (966669).

The spelling of 842421 in words is "eight hundred forty-two thousand, four hundred twenty-one".