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20789 is a prime number
BaseRepresentation
bin101000100110101
31001111222
411010311
51131124
6240125
7114416
oct50465
931458
1020789
111468a
1210045
139602
14780d
15625e
hex5135

20789 has 2 divisors, whose sum is σ = 20790. Its totient is φ = 20788.

The previous prime is 20773. The next prime is 20807. The reversal of 20789 is 98702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20164 + 625 = 142^2 + 25^2 .

It is a cyclic number.

It is not a de Polignac number, because 20789 - 24 = 20773 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a plaindrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10394 + 10395.

It is an arithmetic number, because the mean of its divisors is an integer number (10395).

220789 is an apocalyptic number.

It is an amenable number.

20789 is a deficient number, since it is larger than the sum of its proper divisors (1).

20789 is an equidigital number, since it uses as much as digits as its factorization.

20789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 20789 is about 144.1839103368. The cubic root of 20789 is about 27.4965284874.

The spelling of 20789 in words is "twenty thousand, seven hundred eighty-nine".