280991 has 8 divisors (see below), whose sum is σ = 309120. Its totient is φ = 254232.

The previous prime is 280979. The next prime is 280997. The reversal of 280991 is 199082.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 280991 - 2⁶ = 280927 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 280991.

It is not an unprimeable number, because it can be changed into a prime (280997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116 + ... + 758.

It is an arithmetic number, because the mean of its divisors is an integer number (38640).

2²⁸⁰⁹⁹¹ is an apocalyptic number.

280991 is a deficient number, since it is larger than the sum of its proper divisors (28129).

280991 is a wasteful number, since it uses less digits than its factorization.

280991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 280991 is about 530.0858421048. The cubic root of 280991 is about 65.4984169149.

The spelling of 280991 in words is "two hundred eighty thousand, nine hundred ninety-one".