66660565160981 has 12 divisors (see below), whose sum is σ = 73273216293900. Its totient is φ = 60599119352640.

The previous prime is 66660565160971. The next prime is 66660565161007. The reversal of 66660565160981 is 18906156506666.

It can be written as a sum of positive squares in 2 ways, for example, as 29017247938756 + 37643317222225 = 5386766^2 + 6135415^2 .

It is not a de Polignac number, because 66660565160981 - 2¹⁰ = 66660565159957 is a prime.

It is a super-2 number, since 2×66660565160981² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66660565160921) 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, 1039826 + ... + 11593203.

It is an arithmetic number, because the mean of its divisors is an integer number (6106101357825).

Almost surely, 2^{66660565160981} is an apocalyptic number.

It is an amenable number.

66660565160981 is a deficient number, since it is larger than the sum of its proper divisors (6612651132919).

66660565160981 is a wasteful number, since it uses less digits than its factorization.

66660565160981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12676660 (or 12676649 counting only the distinct ones).

The product of its (nonzero) digits is 83980800, while the sum is 65.

The spelling of 66660565160981 in words is "sixty-six trillion, six hundred sixty billion, five hundred sixty-five million, one hundred sixty thousand, nine hundred eighty-one".