830821 has 4 divisors (see below), whose sum is σ = 859500. Its totient is φ = 802144.

The previous prime is 830801. The next prime is 830827. The reversal of 830821 is 128038.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128038 = 2 ⋅64019.

It can be written as a sum of positive squares in 2 ways, for example, as 408321 + 422500 = 639^2 + 650^2 .

It is a cyclic number.

It is not a de Polignac number, because 830821 - 2⁵ = 830789 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 830792 and 830801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (830827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14296 + ... + 14353.

It is an arithmetic number, because the mean of its divisors is an integer number (214875).

2⁸³⁰⁸²¹ is an apocalyptic number.

It is an amenable number.

830821 is a deficient number, since it is larger than the sum of its proper divisors (28679).

830821 is a wasteful number, since it uses less digits than its factorization.

830821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28678.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 830821 is about 911.4938288326. The cubic root of 830821 is about 94.0089398469.

Adding to 830821 its reverse (128038), we get a palindrome (958859).

The spelling of 830821 in words is "eight hundred thirty thousand, eight hundred twenty-one".