280231921 has 4 divisors (see below), whose sum is σ = 280534500. Its totient is φ = 279929344.

The previous prime is 280231883. The next prime is 280231951. The reversal of 280231921 is 129132082.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 124880625 + 155351296 = 11175^2 + 12464^2 .

It is a cyclic number.

It is not a de Polignac number, because 280231921 - 2¹⁹ = 279707633 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 280231921.

It is not an unprimeable number, because it can be changed into a prime (280231951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 149896 + ... + 151753.

It is an arithmetic number, because the mean of its divisors is an integer number (70133625).

Almost surely, 2^280231921 is an apocalyptic number.

It is an amenable number.

280231921 is a deficient number, since it is larger than the sum of its proper divisors (302579).

280231921 is an equidigital number, since it uses as much as digits as its factorization.

280231921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302578.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 280231921 is about 16740.1290616291. The cubic root of 280231921 is about 654.3938381356.

The spelling of 280231921 in words is "two hundred eighty million, two hundred thirty-one thousand, nine hundred twenty-one".