261281 has 2 divisors, whose sum is σ = 261282. Its totient is φ = 261280.

The previous prime is 261271. The next prime is 261301. The reversal of 261281 is 182162.

It is an a-pointer prime, because the next prime (261301) can be obtained adding 261281 to its sum of digits (20).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 180625 + 80656 = 425^2 + 284^2 .

It is a cyclic number.

It is not a de Polignac number, because 261281 - 2¹⁴ = 244897 is a prime.

It is a super-2 number, since 2×261281² = 136535521922, which contains 22 as substring.

It is a Chen prime.

It is equal to p₂₂₉₃₄ and since 261281 and 22934 have the same sum of digits, it is a Honaker prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 261281.

It is not a weakly prime, because it can be changed into another prime (261241) 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, 130640 + 130641.

It is an arithmetic number, because the mean of its divisors is an integer number (130641).

2²⁶¹²⁸¹ is an apocalyptic number.

It is an amenable number.

261281 is a deficient number, since it is larger than the sum of its proper divisors (1).

261281 is an equidigital number, since it uses as much as digits as its factorization.

261281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 192, while the sum is 20.

The square root of 261281 is about 511.1565317982. The cubic root of 261281 is about 63.9296916700.

The spelling of 261281 in words is "two hundred sixty-one thousand, two hundred eighty-one".