66665605099 has 4 divisors (see below), whose sum is σ = 67011022936. Its totient is φ = 66320187264.

The previous prime is 66665605081. The next prime is 66665605103. The reversal of 66665605099 is 99050656666.

It is a happy number.

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 66665605099 - 2²³ = 66657216491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66665605499) 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, 172708629 + ... + 172709014.

It is an arithmetic number, because the mean of its divisors is an integer number (16752755734).

Almost surely, 2^66665605099 is an apocalyptic number.

66665605099 is a deficient number, since it is larger than the sum of its proper divisors (345417837).

66665605099 is a wasteful number, since it uses less digits than its factorization.

66665605099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345417836.

The product of its (nonzero) digits is 15746400, while the sum is 58.

The spelling of 66665605099 in words is "sixty-six billion, six hundred sixty-five million, six hundred five thousand, ninety-nine".