821099 has 2 divisors, whose sum is σ = 821100. Its totient is φ = 821098.

The previous prime is 821089. The next prime is 821101. The reversal of 821099 is 990128.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821099 is a prime.

Together with 821101, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 15.

It is not a weakly prime, because it can be changed into another prime (821039) 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 as a sum of consecutive naturals, namely, 410549 + 410550.

It is an arithmetic number, because the mean of its divisors is an integer number (410550).

2⁸²¹⁰⁹⁹ is an apocalyptic number.

821099 is a deficient number, since it is larger than the sum of its proper divisors (1).

821099 is an equidigital number, since it uses as much as digits as its factorization.

821099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 821099 is about 906.1451318635. The cubic root of 821099 is about 93.6408127347.

Adding to 821099 its sum of digits (29), we get a palindrome (821128).

The spelling of 821099 in words is "eight hundred twenty-one thousand, ninety-nine".