821868 has 12 divisors (see below), whose sum is σ = 1917720. Its totient is φ = 273952.

The previous prime is 821861. The next prime is 821869. The reversal of 821868 is 868128.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (821861) by changing a digit.

821868 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34233 + ... + 34256.

It is an arithmetic number, because the mean of its divisors is an integer number (159810).

2⁸²¹⁸⁶⁸ is an apocalyptic number.

It is an amenable number.

821868 is an abundant number, since it is smaller than the sum of its proper divisors (1095852).

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

821868 is a wasteful number, since it uses less digits than its factorization.

821868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68496 (or 68494 counting only the distinct ones).

The product of its digits is 6144, while the sum is 33.

The square root of 821868 is about 906.5693575232. The cubic root of 821868 is about 93.6700367042.

The spelling of 821868 in words is "eight hundred twenty-one thousand, eight hundred sixty-eight".