66600111556 has 24 divisors (see below), whose sum is σ = 127167235776. Its totient is φ = 30267642720.

The previous prime is 66600111553. The next prime is 66600111563. The reversal of 66600111556 is 65511100666.

It is a super-2 number, since 2×66600111556² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66600111553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140265 + ... + 390991.

It is an arithmetic number, because the mean of its divisors is an integer number (5298634824).

Almost surely, 2^66600111556 is an apocalyptic number.

It is an amenable number.

66600111556 is a deficient number, since it is larger than the sum of its proper divisors (60567124220).

66600111556 is a wasteful number, since it uses less digits than its factorization.

66600111556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256779 (or 256777 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 37.

The spelling of 66600111556 in words is "sixty-six billion, six hundred million, one hundred eleven thousand, five hundred fifty-six".