280745729 has 24 divisors (see below), whose sum is σ = 328667040. Its totient is φ = 237826800.

The previous prime is 280745681. The next prime is 280745747. The reversal of 280745729 is 927547082.

It is not a de Polignac number, because 280745729 - 2⁸ = 280745473 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 280745729.

It is not an unprimeable number, because it can be changed into a prime (280745749) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4602359 + ... + 4602419.

It is an arithmetic number, because the mean of its divisors is an integer number (13694460).

Almost surely, 2^280745729 is an apocalyptic number.

It is an amenable number.

280745729 is a deficient number, since it is larger than the sum of its proper divisors (47921311).

280745729 is an frugal number, since it uses more digits than its factorization.

280745729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 44.

The square root of 280745729 is about 16755.4686296743. The cubic root of 280745729 is about 654.7935398085.

The spelling of 280745729 in words is "two hundred eighty million, seven hundred forty-five thousand, seven hundred twenty-nine".