20684143 has 2 divisors, whose sum is σ = 20684144. Its totient is φ = 20684142.

The previous prime is 20684117. The next prime is 20684149. The reversal of 20684143 is 34148602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20684143 - 2⁹ = 20683631 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20684149) 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 as a sum of consecutive naturals, namely, 10342071 + 10342072.

It is an arithmetic number, because the mean of its divisors is an integer number (10342072).

Almost surely, 2^20684143 is an apocalyptic number.

20684143 is a deficient number, since it is larger than the sum of its proper divisors (1).

20684143 is an equidigital number, since it uses as much as digits as its factorization.

20684143 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 20684143 is about 4547.9822998776. The cubic root of 20684143 is about 274.5022091100.

The spelling of 20684143 in words is "twenty million, six hundred eighty-four thousand, one hundred forty-three".