821985 has 8 divisors (see below), whose sum is σ = 1315200. Its totient is φ = 438384.

The previous prime is 821971. The next prime is 821993. The reversal of 821985 is 589128.

It is a happy number.

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

It is not a de Polignac number, because 821985 - 2⁷ = 821857 is a prime.

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27385 + ... + 27414.

It is an arithmetic number, because the mean of its divisors is an integer number (164400).

2⁸²¹⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

821985 is a deficient number, since it is larger than the sum of its proper divisors (493215).

821985 is a wasteful number, since it uses less digits than its factorization.

821985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54807.

The product of its digits is 5760, while the sum is 33.

The square root of 821985 is about 906.6338842113. The cubic root of 821985 is about 93.6744814059.

The spelling of 821985 in words is "eight hundred twenty-one thousand, nine hundred eighty-five".