64666254816865 has 16 divisors (see below), whose sum is σ = 84985117156800. Its totient is φ = 46944159947712.

The previous prime is 64666254816853. The next prime is 64666254816883. The reversal of 64666254816865 is 56861845266646.

It is a cyclic number.

It is not a de Polignac number, because 64666254816865 - 2³⁵ = 64631895078497 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8431059375 + ... + 8431067044.

It is an arithmetic number, because the mean of its divisors is an integer number (5311569822300).

Almost surely, 2^{64666254816865} is an apocalyptic number.

64666254816865 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

64666254816865 is a deficient number, since it is larger than the sum of its proper divisors (20318862339935).

64666254816865 is a wasteful number, since it uses less digits than its factorization.

64666254816865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16862126496.

The product of its digits is 2388787200, while the sum is 73.

The spelling of 64666254816865 in words is "sixty-four trillion, six hundred sixty-six billion, two hundred fifty-four million, eight hundred sixteen thousand, eight hundred sixty-five".