66717644012345 has 4 divisors (see below), whose sum is σ = 80061172814820. Its totient is φ = 53374115209872.

The previous prime is 66717644012207. The next prime is 66717644012359. The reversal of 66717644012345 is 54321044671766.

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

It can be written as a sum of positive squares in 2 ways, for example, as 21565547152384 + 45152096859961 = 4643872^2 + 6719531^2 .

It is a cyclic number.

It is not a de Polignac number, because 66717644012345 - 2³⁴ = 66700464143161 is a prime.

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, 6671764401230 + ... + 6671764401239.

It is an arithmetic number, because the mean of its divisors is an integer number (20015293203705).

Almost surely, 2^{66717644012345} is an apocalyptic number.

It is an amenable number.

66717644012345 is a deficient number, since it is larger than the sum of its proper divisors (13343528802475).

66717644012345 is a wasteful number, since it uses less digits than its factorization.

66717644012345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13343528802474.

The product of its (nonzero) digits is 20321280, while the sum is 56.

The spelling of 66717644012345 in words is "sixty-six trillion, seven hundred seventeen billion, six hundred forty-four million, twelve thousand, three hundred forty-five".