66735660665 has 4 divisors (see below), whose sum is σ = 80082792804. Its totient is φ = 53388528528.

The previous prime is 66735660659. The next prime is 66735660727. The reversal of 66735660665 is 56606653766.

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 10858265209 + 55877395456 = 104203^2 + 236384^2 .

It is a cyclic number.

It is not a de Polignac number, because 66735660665 - 2²⁴ = 66718883449 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66735660665.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6673566062 + ... + 6673566071.

It is an arithmetic number, because the mean of its divisors is an integer number (20020698201).

Almost surely, 2^66735660665 is an apocalyptic number.

It is an amenable number.

66735660665 is a deficient number, since it is larger than the sum of its proper divisors (13347132139).

66735660665 is a wasteful number, since it uses less digits than its factorization.

66735660665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13347132138.

The product of its (nonzero) digits is 24494400, while the sum is 56.

The spelling of 66735660665 in words is "sixty-six billion, seven hundred thirty-five million, six hundred sixty thousand, six hundred sixty-five".