8500920721 has 2 divisors, whose sum is σ = 8500920722. Its totient is φ = 8500920720.

The previous prime is 8500920709. The next prime is 8500920761. The reversal of 8500920721 is 1270290058.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4261478400 + 4239442321 = 65280^2 + 65111^2 .

It is a cyclic number.

It is not a de Polignac number, because 8500920721 - 2¹⁵ = 8500887953 is a prime.

It is not a weakly prime, because it can be changed into another prime (8500920761) 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, 4250460360 + 4250460361.

It is an arithmetic number, because the mean of its divisors is an integer number (4250460361).

Almost surely, 2^8500920721 is an apocalyptic number.

It is an amenable number.

8500920721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8500920721 is an equidigital number, since it uses as much as digits as its factorization.

8500920721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 8500920721 is about 92200.4377484185. The cubic root of 8500920721 is about 2040.9012358584.

The spelling of 8500920721 in words is "eight billion, five hundred million, nine hundred twenty thousand, seven hundred twenty-one".