66611818 has 32 divisors (see below), whose sum is σ = 128330496. Its totient is φ = 25204608.

The previous prime is 66611813. The next prime is 66611819. The reversal of 66611818 is 81811666.

It is a happy number.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (66611813) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3771 + ... + 12142.

It is an arithmetic number, because the mean of its divisors is an integer number (4010328).

Almost surely, 2^66611818 is an apocalyptic number.

66611818 is a deficient number, since it is larger than the sum of its proper divisors (61718678).

66611818 is a wasteful number, since it uses less digits than its factorization.

66611818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15958.

The product of its digits is 13824, while the sum is 37.

The square root of 66611818 is about 8161.6063369903. The cubic root of 66611818 is about 405.3689023051.

The spelling of 66611818 in words is "sixty-six million, six hundred eleven thousand, eight hundred eighteen".