20666118 has 64 divisors (see below), whose sum is σ = 48460032. Its totient is φ = 5806080.

The previous prime is 20666111. The next prime is 20666143. The reversal of 20666118 is 81166602.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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 (20666111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 126705 + ... + 126867.

It is an arithmetic number, because the mean of its divisors is an integer number (757188).

Almost surely, 2^20666118 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20666118, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24230016).

20666118 is an abundant number, since it is smaller than the sum of its proper divisors (27793914).

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

20666118 is a wasteful number, since it uses less digits than its factorization.

20666118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 20666118 is about 4546.0002199736. Note that the first 3 decimals coincide. The cubic root of 20666118 is about 274.4224484889.

The spelling of 20666118 in words is "twenty million, six hundred sixty-six thousand, one hundred eighteen".