821385 has 12 divisors (see below), whose sum is σ = 1423812. Its totient is φ = 438048.

The previous prime is 821383. The next prime is 821411. The reversal of 821385 is 583128.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 95481 + 725904 = 309^2 + 852^2 .

It is not a de Polignac number, because 821385 - 2¹ = 821383 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

821385 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 821385.

It is not an unprimeable number, because it can be changed into a prime (821383) 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 11 ways as a sum of consecutive naturals, for example, 9082 + ... + 9171.

It is an arithmetic number, because the mean of its divisors is an integer number (118651).

2⁸²¹³⁸⁵ is an apocalyptic number.

It is an amenable number.

821385 is a deficient number, since it is larger than the sum of its proper divisors (602427).

821385 is a wasteful number, since it uses less digits than its factorization.

821385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18264 (or 18261 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 821385 is about 906.3029294888. The cubic root of 821385 is about 93.6516835975.

The spelling of 821385 in words is "eight hundred twenty-one thousand, three hundred eighty-five".