280723 has 4 divisors (see below), whose sum is σ = 281880. Its totient is φ = 279568.

The previous prime is 280717. The next prime is 280729. The reversal of 280723 is 327082.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (280717) and next prime (280729).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-280723 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 280694 and 280703.

It is not an unprimeable number, because it can be changed into a prime (280729) 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 in 3 ways as a sum of consecutive naturals, for example, 58 + ... + 751.

It is an arithmetic number, because the mean of its divisors is an integer number (70470).

2²⁸⁰⁷²³ is an apocalyptic number.

280723 is a deficient number, since it is larger than the sum of its proper divisors (1157).

280723 is an equidigital number, since it uses as much as digits as its factorization.

280723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1156.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 280723 is about 529.8329925552. The cubic root of 280723 is about 65.4775868772.

The spelling of 280723 in words is "two hundred eighty thousand, seven hundred twenty-three".