20666117 has 4 divisors (see below), whose sum is σ = 20679660. Its totient is φ = 20652576.

The previous prime is 20666111. The next prime is 20666143. The reversal of 20666117 is 71166602.

It is a Cunningham number, because it is equal to 4546²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 586756 + 20079361 = 766^2 + 4481^2 .

It is a cyclic number.

It is not a de Polignac number, because 20666117 - 2¹⁰ = 20665093 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20666117.

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 3 ways as a sum of consecutive naturals, for example, 4142 + ... + 7647.

It is an arithmetic number, because the mean of its divisors is an integer number (5169915).

Almost surely, 2^20666117 is an apocalyptic number.

It is an amenable number.

20666117 is a deficient number, since it is larger than the sum of its proper divisors (13543).

20666117 is a wasteful number, since it uses less digits than its factorization.

20666117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13542.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 20666117 is about 4546.0001099868. Note that the first 3 decimals coincide. The cubic root of 20666117 is about 274.4224440626.

The spelling of 20666117 in words is "twenty million, six hundred sixty-six thousand, one hundred seventeen".