821838 has 8 divisors (see below), whose sum is σ = 1643688. Its totient is φ = 273944.

The previous prime is 821833. The next prime is 821851. The reversal of 821838 is 838128.

It is a sphenic number, since it is the product of 3 distinct primes.

821838 is an admirable 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 821838.

It is not an unprimeable number, because it can be changed into a prime (821833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68481 + ... + 68492.

It is an arithmetic number, because the mean of its divisors is an integer number (205461).

2⁸²¹⁸³⁸ is an apocalyptic number.

821838 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

821838 is a wasteful number, since it uses less digits than its factorization.

821838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136978.

The product of its digits is 3072, while the sum is 30.

The square root of 821838 is about 906.5528114787. The cubic root of 821838 is about 93.6688969692.

Subtracting 821838 from its reverse (838128), we obtain a triangular number (16290 = T₁₈₀).

It can be divided in two parts, 8218 and 38, that added together give a triangular number (8256 = T₁₂₈).

The spelling of 821838 in words is "eight hundred twenty-one thousand, eight hundred thirty-eight".