821797 has 4 divisors (see below), whose sum is σ = 870156. Its totient is φ = 773440.

The previous prime is 821771. The next prime is 821801. The reversal of 821797 is 797128.

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

It can be written as a sum of positive squares in 2 ways, for example, as 662596 + 159201 = 814^2 + 399^2 .

It is a cyclic number.

It is not a de Polignac number, because 821797 - 2¹⁵ = 789029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821747) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24154 + ... + 24187.

It is an arithmetic number, because the mean of its divisors is an integer number (217539).

2⁸²¹⁷⁹⁷ is an apocalyptic number.

It is an amenable number.

821797 is a deficient number, since it is larger than the sum of its proper divisors (48359).

821797 is a wasteful number, since it uses less digits than its factorization.

821797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48358.

The product of its digits is 7056, while the sum is 34.

The square root of 821797 is about 906.5301980629. The cubic root of 821797 is about 93.6673392864.

The spelling of 821797 in words is "eight hundred twenty-one thousand, seven hundred ninety-seven".