280021 has 8 divisors (see below), whose sum is σ = 323840. Its totient is φ = 237168.

The previous prime is 280013. The next prime is 280031. The reversal of 280021 is 120082.

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 280021 - 2³ = 280013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 279983 and 280010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (280001) 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, 580 + ... + 946.

It is an arithmetic number, because the mean of its divisors is an integer number (40480).

2²⁸⁰⁰²¹ is an apocalyptic number.

It is an amenable number.

280021 is a deficient number, since it is larger than the sum of its proper divisors (43819).

280021 is a wasteful number, since it uses less digits than its factorization.

280021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 483.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 280021 is about 529.1701049757. The cubic root of 280021 is about 65.4229616960.

The spelling of 280021 in words is "two hundred eighty thousand, twenty-one".