280906 has 4 divisors (see below), whose sum is σ = 421362. Its totient is φ = 140452.

The previous prime is 280897. The next prime is 280909. The reversal of 280906 is 609082.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 609082 = 2 ⋅304541.

It can be written as a sum of positive squares in only one way, i.e., 210681 + 70225 = 459^2 + 265^2 .

It is a plaindrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (280909) 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, 70225 + ... + 70228.

2²⁸⁰⁹⁰⁶ is an apocalyptic number.

280906 is a deficient number, since it is larger than the sum of its proper divisors (140456).

280906 is a wasteful number, since it uses less digits than its factorization.

280906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140455.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 280906 is about 530.0056603471. The cubic root of 280906 is about 65.4918118079.

Adding to 280906 its reverse (609082), we get a palindrome (889988).

It can be divided in two parts, 2 and 80906, that added together give a palindrome (80908).

The spelling of 280906 in words is "two hundred eighty thousand, nine hundred six".