821684533 has 2 divisors, whose sum is σ = 821684534. Its totient is φ = 821684532.

The previous prime is 821684527. The next prime is 821684573. The reversal of 821684533 is 335486128.

It is an a-pointer prime, because the next prime (821684573) can be obtained adding 821684533 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 821567569 + 116964 = 28663^2 + 342^2 .

It is a cyclic number.

It is not a de Polignac number, because 821684533 - 2⁹ = 821684021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821684573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410842266 + 410842267.

It is an arithmetic number, because the mean of its divisors is an integer number (410842267).

Almost surely, 2^821684533 is an apocalyptic number.

It is an amenable number.

821684533 is a deficient number, since it is larger than the sum of its proper divisors (1).

821684533 is an equidigital number, since it uses as much as digits as its factorization.

821684533 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 138240, while the sum is 40.

The square root of 821684533 is about 28665.0402581263. The cubic root of 821684533 is about 936.6306614467.

The spelling of 821684533 in words is "eight hundred twenty-one million, six hundred eighty-four thousand, five hundred thirty-three".