280981 has 4 divisors (see below), whose sum is σ = 290700. Its totient is φ = 271264.

The previous prime is 280979. The next prime is 280997. The reversal of 280981 is 189082.

280981 = T₆₈ + T₆₉ + ... + T₁₂₅.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 189082 = 2 ⋅94541.

It can be written as a sum of positive squares in 2 ways, for example, as 152100 + 128881 = 390^2 + 359^2 .

It is a cyclic number.

It is not a de Polignac number, because 280981 - 2¹ = 280979 is a prime.

It is a super-2 number, since 2×280981² = 157900644722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (280921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4816 + ... + 4873.

It is an arithmetic number, because the mean of its divisors is an integer number (72675).

2²⁸⁰⁹⁸¹ is an apocalyptic number.

It is an amenable number.

280981 is a deficient number, since it is larger than the sum of its proper divisors (9719).

280981 is an equidigital number, since it uses as much as digits as its factorization.

280981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9718.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 280981 is about 530.0764095864. The cubic root of 280981 is about 65.4976399126.

It can be divided in two parts, 2809 and 81, that multiplied together give a square (227529 = 477²).

The spelling of 280981 in words is "two hundred eighty thousand, nine hundred eighty-one".