161281 has 2 divisors, whose sum is σ = 161282. Its totient is φ = 161280.

The previous prime is 161267. The next prime is 161303. The reversal of 161281 is 182161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 128881 + 32400 = 359^2 + 180^2 .

It is a cyclic number.

It is not a de Polignac number, because 161281 - 2¹¹ = 159233 is a prime.

It is a super-2 number, since 2×161281² = 52023121922, which contains 22 as substring.

161281 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (161201) 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, 80640 + 80641.

It is an arithmetic number, because the mean of its divisors is an integer number (80641).

It is a Proth number, since it is equal to 315 ⋅ 2⁹ + 1 and 315 < 2⁹.

2¹⁶¹²⁸¹ is an apocalyptic number.

It is an amenable number.

161281 is a deficient number, since it is larger than the sum of its proper divisors (1).

161281 is an equidigital number, since it uses as much as digits as its factorization.

161281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 19.

The square root of 161281 is about 401.5980577642. The cubic root of 161281 is about 54.4328494289.

It can be divided in two parts, 16128 and 1, that added together give a square (16129 = 127²).

The spelling of 161281 in words is "one hundred sixty-one thousand, two hundred eighty-one".