8331566821 has 2 divisors, whose sum is σ = 8331566822. Its totient is φ = 8331566820.

The previous prime is 8331566807. The next prime is 8331566849. The reversal of 8331566821 is 1286651338.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6858158596 + 1473408225 = 82814^2 + 38385^2 .

It is a cyclic number.

It is not a de Polignac number, because 8331566821 - 2⁷ = 8331566693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8331566801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4165783410 + 4165783411.

It is an arithmetic number, because the mean of its divisors is an integer number (4165783411).

Almost surely, 2^8331566821 is an apocalyptic number.

It is an amenable number.

8331566821 is a deficient number, since it is larger than the sum of its proper divisors (1).

8331566821 is an equidigital number, since it uses as much as digits as its factorization.

8331566821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 207360, while the sum is 43.

The square root of 8331566821 is about 91277.4168181813. The cubic root of 8331566821 is about 2027.2573979361.

The spelling of 8331566821 in words is "eight billion, three hundred thirty-one million, five hundred sixty-six thousand, eight hundred twenty-one".