66317717664 has 72 divisors (see below), whose sum is σ = 205735656672. Its totient is φ = 20096277120.

The previous prime is 66317717663. The next prime is 66317717693. The reversal of 66317717664 is 46671771366.

It is a tau number, because it is divible by the number of its divisors (72).

It is a self number, because there is not a number n which added to its sum of digits gives 66317717664.

It is not an unprimeable number, because it can be changed into a prime (66317717663) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10463644 + ... + 10469979.

It is an arithmetic number, because the mean of its divisors is an integer number (2857439676).

Almost surely, 2^66317717664 is an apocalyptic number.

It is an amenable number.

66317717664 is an abundant number, since it is smaller than the sum of its proper divisors (139417939008).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66317717664 is a wasteful number, since it uses less digits than its factorization.

66317717664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20933650 (or 20933639 counting only the distinct ones).

The product of its digits is 5334336, while the sum is 54.

The spelling of 66317717664 in words is "sixty-six billion, three hundred seventeen million, seven hundred seventeen thousand, six hundred sixty-four".