20771 has 2 divisors, whose sum is σ = 20772. Its totient is φ = 20770.
The previous prime is 20759. The next prime is 20773. The reversal of 20771 is 17702.
It is a happy number.
It is a strong prime.
It is a cyclic number.
It is not a de Polignac number, because 20771 - 26 = 20707 is a prime.
It is a Sophie Germain prime.
Together with 20773, it forms a pair of twin primes.
It is a Chen prime.
It is not a weakly prime, because it can be changed into another prime (20773) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10385 + 10386.
It is an arithmetic number, because the mean of its divisors is an integer number (10386).
220771 is an apocalyptic number.
20771 is a deficient number, since it is larger than the sum of its proper divisors (1).
20771 is an equidigital number, since it uses as much as digits as its factorization.
20771 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 98, while the sum is 17.
The square root of 20771 is about 144.1214765398. The cubic root of 20771 is about 27.4885903081.
The spelling of 20771 in words is "twenty thousand, seven hundred seventy-one", and thus it is an iban number.
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