66699299665 has 4 divisors (see below), whose sum is σ = 80039159604. Its totient is φ = 53359439728.

The previous prime is 66699299659. The next prime is 66699299677. The reversal of 66699299665 is 56699299666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 46670257089 + 20029042576 = 216033^2 + 141524^2 .

It is a cyclic number.

It is not a de Polignac number, because 66699299665 - 2⁵ = 66699299633 is a prime.

It is a super-2 number, since 2×66699299665² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 6669929962 + ... + 6669929971.

It is an arithmetic number, because the mean of its divisors is an integer number (20009789901).

Almost surely, 2^66699299665 is an apocalyptic number.

It is an amenable number.

66699299665 is a deficient number, since it is larger than the sum of its proper divisors (13339859939).

66699299665 is a wasteful number, since it uses less digits than its factorization.

66699299665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13339859938.

The product of its digits is 510183360, while the sum is 73.

Subtracting from 66699299665 its reverse (56699299666), we obtain a palindrome (9999999999).

The spelling of 66699299665 in words is "sixty-six billion, six hundred ninety-nine million, two hundred ninety-nine thousand, six hundred sixty-five".