821442 has 16 divisors (see below), whose sum is σ = 1664640. Its totient is φ = 270192.

The previous prime is 821441. The next prime is 821449. The reversal of 821442 is 244128.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (821441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 393 + ... + 1340.

It is an arithmetic number, because the mean of its divisors is an integer number (104040).

2⁸²¹⁴⁴² is an apocalyptic number.

821442 is an abundant number, since it is smaller than the sum of its proper divisors (843198).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821442 is a wasteful number, since it uses less digits than its factorization.

821442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1817.

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

The square root of 821442 is about 906.3343753825. The cubic root of 821442 is about 93.6538498664.

It can be divided in two parts, 8214 and 42, that added together give a triangular number (8256 = T₁₂₈).

The spelling of 821442 in words is "eight hundred twenty-one thousand, four hundred forty-two".