8130821 has 2 divisors, whose sum is σ = 8130822. Its totient is φ = 8130820.

The previous prime is 8130809. The next prime is 8130839. The reversal of 8130821 is 1280318.

8130821 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6477025 + 1653796 = 2545^2 + 1286^2 .

It is a cyclic number.

It is not a de Polignac number, because 8130821 - 2⁶ = 8130757 is a prime.

It is a super-2 number, since 2×8130821² = 132220500268082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8130851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4065410 + 4065411.

It is an arithmetic number, because the mean of its divisors is an integer number (4065411).

Almost surely, 2^8130821 is an apocalyptic number.

It is an amenable number.

8130821 is a deficient number, since it is larger than the sum of its proper divisors (1).

8130821 is an equidigital number, since it uses as much as digits as its factorization.

8130821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 8130821 is about 2851.4594508777. The cubic root of 8130821 is about 201.0842859963.

The spelling of 8130821 in words is "eight million, one hundred thirty thousand, eight hundred twenty-one".