66411205505 has 4 divisors (see below), whose sum is σ = 79693446612. Its totient is φ = 53128964400.

The previous prime is 66411205499. The next prime is 66411205547. The reversal of 66411205505 is 50550211466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50550211466 = 2 ⋅25275105733.

It can be written as a sum of positive squares in 2 ways, for example, as 48765005584 + 17646199921 = 220828^2 + 132839^2 .

It is not a de Polignac number, because 66411205505 - 2¹⁶ = 66411139969 is a prime.

It is a Duffinian number.

It is a Curzon 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, 6641120546 + ... + 6641120555.

It is an arithmetic number, because the mean of its divisors is an integer number (19923361653).

Almost surely, 2^66411205505 is an apocalyptic number.

It is an amenable number.

66411205505 is a deficient number, since it is larger than the sum of its proper divisors (13282241107).

66411205505 is a wasteful number, since it uses less digits than its factorization.

66411205505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13282241106.

The product of its (nonzero) digits is 36000, while the sum is 35.

The spelling of 66411205505 in words is "sixty-six billion, four hundred eleven million, two hundred five thousand, five hundred five".