20666143 has 2 divisors, whose sum is σ = 20666144. Its totient is φ = 20666142.

The previous prime is 20666111. The next prime is 20666147. The reversal of 20666143 is 34166602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20666143 - 2⁵ = 20666111 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20666147) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10333071 + 10333072.

It is an arithmetic number, because the mean of its divisors is an integer number (10333072).

Almost surely, 2^20666143 is an apocalyptic number.

20666143 is a deficient number, since it is larger than the sum of its proper divisors (1).

20666143 is an equidigital number, since it uses as much as digits as its factorization.

20666143 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 20666143 is about 4546.0029696427. The cubic root of 20666143 is about 274.4225591460.

The spelling of 20666143 in words is "twenty million, six hundred sixty-six thousand, one hundred forty-three".