8639966509 has 4 divisors (see below), whose sum is σ = 8656550460. Its totient is φ = 8623382560.

The previous prime is 8639966497. The next prime is 8639966521. The reversal of 8639966509 is 9056699368.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (8639966497) and next prime (8639966521).

It can be written as a sum of positive squares in 2 ways, for example, as 3894134409 + 4745832100 = 62403^2 + 68890^2 .

It is a cyclic number.

It is not a de Polignac number, because 8639966509 - 2¹⁵ = 8639933741 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8639969509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8291194 + ... + 8292235.

It is an arithmetic number, because the mean of its divisors is an integer number (2164137615).

Almost surely, 2^8639966509 is an apocalyptic number.

It is an amenable number.

8639966509 is a deficient number, since it is larger than the sum of its proper divisors (16583951).

8639966509 is a wasteful number, since it uses less digits than its factorization.

8639966509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16583950.

The product of its (nonzero) digits is 18895680, while the sum is 61.

The square root of 8639966509 is about 92951.4201559072. The cubic root of 8639966509 is about 2051.9684846751.

The spelling of 8639966509 in words is "eight billion, six hundred thirty-nine million, nine hundred sixty-six thousand, five hundred nine".