281 has 2 divisors, whose sum is σ = 282.
Its totient is φ = 280.
The previous prime is 277. The next prime is 283. The reversal of 281 is 182.
281 is nontrivially palindromic in base 14.
281 is an esthetic number in base 4, because in such base it adjacent digits differ by 1.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 256 + 25 = 16^2 + 5^2
It is a cyclic number.
It is not a de Polignac number, because 281 - 22 = 277 is a prime.
It is a super-2 number, since 2×2812 = 157922, which contains 22 as substring.
It is a Sophie Germain prime.
Together with 283, it forms a pair of twin primes.
It is a Chen prime.
It is a magnanimous number.
281 is an undulating number in base 14.
It is a Curzon number.
It is a plaindrome in base 6, base 11, base 13, base 15 and base 16.
It is a nialpdrome in base 5, base 7 and base 8.
It is not a weakly prime, because it can be changed into another prime (283) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140 + 141.
It is an arithmetic number, because the mean of its divisors is an integer number (141).
281 is the 8-th centered decagonal number.
It is an amenable number.
281 is a deficient number, since it is larger than the sum of its proper divisors (1).
281 is an equidigital number, since it uses as much as digits as its factorization.
281 is an evil number, because the sum of its binary digits is even.
The product of its digits is 16, while the sum is 11.
The square root of 281 is about 16.7630546142.
The cubic root of 281 is about 6.5499116201.
The spelling of 281 in words is "two hundred eighty-one", and is thus an aban number.