20728271 has 2 divisors, whose sum is σ = 20728272. Its totient is φ = 20728270.

The previous prime is 20728249. The next prime is 20728273. The reversal of 20728271 is 17282702.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20728271 is a prime.

It is a super-2 number, since 2×20728271² = 859322437298882, which contains 22 as substring.

Together with 20728273, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20728273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10364135 + 10364136.

It is an arithmetic number, because the mean of its divisors is an integer number (10364136).

Almost surely, 2^20728271 is an apocalyptic number.

20728271 is a deficient number, since it is larger than the sum of its proper divisors (1).

20728271 is an equidigital number, since it uses as much as digits as its factorization.

20728271 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 20728271 is about 4552.8310972405. The cubic root of 20728271 is about 274.6972801115.

The spelling of 20728271 in words is "twenty million, seven hundred twenty-eight thousand, two hundred seventy-one".