821878 has 8 divisors (see below), whose sum is σ = 1236672. Its totient is φ = 409656.

The previous prime is 821869. The next prime is 821879. The reversal of 821878 is 878128.

821878 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821879) by changing a digit.

821878 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, 876 + ... + 1552.

It is an arithmetic number, because the mean of its divisors is an integer number (154584).

2⁸²¹⁸⁷⁸ is an apocalyptic number.

821878 is a deficient number, since it is larger than the sum of its proper divisors (414794).

821878 is a wasteful number, since it uses less digits than its factorization.

821878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1286.

The product of its digits is 7168, while the sum is 34.

The square root of 821878 is about 906.5748728042. The cubic root of 821878 is about 93.6704166098.

The spelling of 821878 in words is "eight hundred twenty-one thousand, eight hundred seventy-eight".