66956859599 has 4 divisors (see below), whose sum is σ = 76522125264. Its totient is φ = 57391593936.

The previous prime is 66956859589. The next prime is 66956859623. The reversal of 66956859599 is 99595865966.

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

It is a cyclic number.

It is not a de Polignac number, because 66956859599 - 2²⁴ = 66940082383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66956859589) 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, 4782632822 + ... + 4782632835.

It is an arithmetic number, because the mean of its divisors is an integer number (19130531316).

Almost surely, 2^66956859599 is an apocalyptic number.

66956859599 is a deficient number, since it is larger than the sum of its proper divisors (9565265665).

66956859599 is an equidigital number, since it uses as much as digits as its factorization.

66956859599 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9565265664.

The product of its digits is 1417176000, while the sum is 77.

The spelling of 66956859599 in words is "sixty-six billion, nine hundred fifty-six million, eight hundred fifty-nine thousand, five hundred ninety-nine".