422821 has 6 divisors (see below), whose sum is σ = 491910. Its totient is φ = 362376.

The previous prime is 422803. The next prime is 422827. The reversal of 422821 is 128224.

It can be written as a sum of positive squares in only one way, i.e., 396900 + 25921 = 630^2 + 161^2 .

It is not a de Polignac number, because 422821 - 2⁵ = 422789 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (422827) 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, 4266 + ... + 4363.

It is an arithmetic number, because the mean of its divisors is an integer number (81985).

2⁴²²⁸²¹ is an apocalyptic number.

It is an amenable number.

422821 is a deficient number, since it is larger than the sum of its proper divisors (69089).

422821 is an equidigital number, since it uses as much as digits as its factorization.

422821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8643 (or 8636 counting only the distinct ones).

The product of its digits is 256, while the sum is 19.

The square root of 422821 is about 650.2468761940. The cubic root of 422821 is about 75.0560174095.

It can be divided in two parts, 4228 and 21, that multiplied together give a palindrome (88788).

The spelling of 422821 in words is "four hundred twenty-two thousand, eight hundred twenty-one".