280909 has 2 divisors, whose sum is σ = 280910. Its totient is φ = 280908.

The previous prime is 280897. The next prime is 280913. The reversal of 280909 is 909082.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 280900 + 9 = 530^2 + 3^2 .

It is a cyclic number.

It is not a de Polignac number, because 280909 - 2¹³ = 272717 is a prime.

It is a Chen prime.

It is an Ulam number.

280909 is a modest number, since divided by 909 gives 28 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (280939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140454 + 140455.

It is an arithmetic number, because the mean of its divisors is an integer number (140455).

2²⁸⁰⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

280909 is a deficient number, since it is larger than the sum of its proper divisors (1).

280909 is an equidigital number, since it uses as much as digits as its factorization.

280909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 280909 is about 530.0084904980. The cubic root of 280909 is about 65.4920449520.

The spelling of 280909 in words is "two hundred eighty thousand, nine hundred nine".