66051566217 has 24 divisors (see below), whose sum is σ = 117425008064. Its totient is φ = 34840386144.

The previous prime is 66051566197. The next prime is 66051566219. The reversal of 66051566217 is 71266515066.

66051566217 is a `hidden beast` number, since 6 + 6 + 0 + 5 + 15 + 6 + 621 + 7 = 666.

It is not a de Polignac number, because 66051566217 - 2⁶ = 66051566153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66051566219) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 40323703 + ... + 40325340.

Almost surely, 2^66051566217 is an apocalyptic number.

It is an amenable number.

66051566217 is a deficient number, since it is larger than the sum of its proper divisors (51373441847).

66051566217 is a wasteful number, since it uses less digits than its factorization.

66051566217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80649069 (or 80649066 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 45.

The spelling of 66051566217 in words is "sixty-six billion, fifty-one million, five hundred sixty-six thousand, two hundred seventeen".