66806066815 has 4 divisors (see below), whose sum is σ = 80167280184. Its totient is φ = 53444853448.

The previous prime is 66806066809. The next prime is 66806066827. The reversal of 66806066815 is 51866060866.

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 66806066815 - 2²¹ = 66803969663 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 6680606677 + ... + 6680606686.

It is an arithmetic number, because the mean of its divisors is an integer number (20041820046).

Almost surely, 2^66806066815 is an apocalyptic number.

66806066815 is a deficient number, since it is larger than the sum of its proper divisors (13361213369).

66806066815 is a wasteful number, since it uses less digits than its factorization.

66806066815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13361213368.

The product of its (nonzero) digits is 2488320, while the sum is 52.

The spelling of 66806066815 in words is "sixty-six billion, eight hundred six million, sixty-six thousand, eight hundred fifteen".