66185561412 has 18 divisors (see below), whose sum is σ = 167302391438. Its totient is φ = 22061853792.

The previous prime is 66185561363. The next prime is 66185561413. The reversal of 66185561412 is 21416558166.

66185561412 is a `hidden beast` number, since 6 + 6 + 1 + 85 + 561 + 4 + 1 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 61378080516 + 4807480896 = 247746^2 + 69336^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (66185561413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 919243873 + ... + 919243944.

Almost surely, 2^66185561412 is an apocalyptic number.

It is an amenable number.

66185561412 is an abundant number, since it is smaller than the sum of its proper divisors (101116830026).

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

66185561412 is a wasteful number, since it uses less digits than its factorization.

66185561412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1838487827 (or 1838487822 counting only the distinct ones).

The product of its digits is 345600, while the sum is 45.

The spelling of 66185561412 in words is "sixty-six billion, one hundred eighty-five million, five hundred sixty-one thousand, four hundred twelve".