8135821 has 2 divisors, whose sum is σ = 8135822. Its totient is φ = 8135820.

The previous prime is 8135801. The next prime is 8135833. The reversal of 8135821 is 1285318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8037225 + 98596 = 2835^2 + 314^2 .

It is a cyclic number.

It is not a de Polignac number, because 8135821 - 2⁵ = 8135789 is a prime.

It is a Chen prime.

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 8135821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8135801) 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, 4067910 + 4067911.

It is an arithmetic number, because the mean of its divisors is an integer number (4067911).

Almost surely, 2^8135821 is an apocalyptic number.

It is an amenable number.

8135821 is a deficient number, since it is larger than the sum of its proper divisors (1).

8135821 is an equidigital number, since it uses as much as digits as its factorization.

8135821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1920, while the sum is 28.

The square root of 8135821 is about 2852.3360601444. The cubic root of 8135821 is about 201.1254960786.

The spelling of 8135821 in words is "eight million, one hundred thirty-five thousand, eight hundred twenty-one".