861307021 has 2 divisors, whose sum is σ = 861307022. Its totient is φ = 861307020.

The previous prime is 861306937. The next prime is 861307033. The reversal of 861307021 is 120703168.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 614345796 + 246961225 = 24786^2 + 15715^2 .

It is a cyclic number.

It is not a de Polignac number, because 861307021 - 2¹⁹ = 860782733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861307061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430653510 + 430653511.

It is an arithmetic number, because the mean of its divisors is an integer number (430653511).

Almost surely, 2^861307021 is an apocalyptic number.

It is an amenable number.

861307021 is a deficient number, since it is larger than the sum of its proper divisors (1).

861307021 is an equidigital number, since it uses as much as digits as its factorization.

861307021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 861307021 is about 29348.0326597883. The cubic root of 861307021 is about 951.4500555372.

The spelling of 861307021 in words is "eight hundred sixty-one million, three hundred seven thousand, twenty-one".