821798 has 4 divisors (see below), whose sum is σ = 1232700. Its totient is φ = 410898.

The previous prime is 821771. The next prime is 821801. The reversal of 821798 is 897128.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 821798.

It is an unprimeable number.

821798 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 as a sum of consecutive naturals, namely, 205448 + ... + 205451.

It is an arithmetic number, because the mean of its divisors is an integer number (308175).

2⁸²¹⁷⁹⁸ is an apocalyptic number.

821798 is a deficient number, since it is larger than the sum of its proper divisors (410902).

821798 is a wasteful number, since it uses less digits than its factorization.

821798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410901.

The product of its digits is 8064, while the sum is 35.

The square root of 821798 is about 906.5307496164. The cubic root of 821798 is about 93.6673772793.

The spelling of 821798 in words is "eight hundred twenty-one thousand, seven hundred ninety-eight".