8509285721 has 2 divisors, whose sum is σ = 8509285722. Its totient is φ = 8509285720.

The previous prime is 8509285709. The next prime is 8509285777. The reversal of 8509285721 is 1275829058.

8509285721 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., 5096389321 + 3412896400 = 71389^2 + 58420^2 .

It is a cyclic number.

It is not a de Polignac number, because 8509285721 - 2¹⁰ = 8509284697 is a prime.

It is a super-2 number, since 2×8509285721² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (8509285021) 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, 4254642860 + 4254642861.

It is an arithmetic number, because the mean of its divisors is an integer number (4254642861).

Almost surely, 2^8509285721 is an apocalyptic number.

It is an amenable number.

8509285721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8509285721 is an equidigital number, since it uses as much as digits as its factorization.

8509285721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 403200, while the sum is 47.

The square root of 8509285721 is about 92245.7897196398. The cubic root of 8509285721 is about 2041.5704395338.

The spelling of 8509285721 in words is "eight billion, five hundred nine million, two hundred eighty-five thousand, seven hundred twenty-one".