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20710309 is a prime number
BaseRepresentation
bin100111100000…
…0001110100101
31102222012012111
41033000032211
520300212214
62015521021
7341014624
oct117001645
942865174
1020710309
1110765a64
126b29171
1343a1829
142a716bb
151c415c4
hex13c03a5

20710309 has 2 divisors, whose sum is σ = 20710310. Its totient is φ = 20710308.

The previous prime is 20710307. The next prime is 20710331. The reversal of 20710309 is 90301702.

It is an a-pointer prime, because the next prime (20710331) can be obtained adding 20710309 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18679684 + 2030625 = 4322^2 + 1425^2 .

It is a cyclic number.

It is not a de Polignac number, because 20710309 - 21 = 20710307 is a prime.

Together with 20710307, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20710309.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20710307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10355154 + 10355155.

It is an arithmetic number, because the mean of its divisors is an integer number (10355155).

Almost surely, 220710309 is an apocalyptic number.

It is an amenable number.

20710309 is a deficient number, since it is larger than the sum of its proper divisors (1).

20710309 is an equidigital number, since it uses as much as digits as its factorization.

20710309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 378, while the sum is 22.

The square root of 20710309 is about 4550.8580509614. The cubic root of 20710309 is about 274.6179112398.

The spelling of 20710309 in words is "twenty million, seven hundred ten thousand, three hundred nine".