84821 has 6 divisors (see below), whose sum is σ = 93366. Its totient is φ = 77000.

The previous prime is 84811. The next prime is 84827. The reversal of 84821 is 12848.

It can be written as a sum of positive squares in only one way, i.e., 81796 + 3025 = 286^2 + 55^2 .

It is not a de Polignac number, because 84821 - 2¹⁴ = 68437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84827) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 230 + ... + 471.

It is an arithmetic number, because the mean of its divisors is an integer number (15561).

2⁸⁴⁸²¹ is an apocalyptic number.

It is an amenable number.

84821 is a deficient number, since it is larger than the sum of its proper divisors (8545).

84821 is a wasteful number, since it uses less digits than its factorization.

84821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 723 (or 712 counting only the distinct ones).

The product of its digits is 512, while the sum is 23.

The square root of 84821 is about 291.2404504872. The cubic root of 84821 is about 43.9374110108.

The spelling of 84821 in words is "eighty-four thousand, eight hundred twenty-one".