280560640 has 88 divisors (see below), whose sum is σ = 691673112. Its totient is φ = 109117440.

The previous prime is 280560629. The next prime is 280560649. The reversal of 280560640 is 46065082.

It can be written as a sum of positive squares in 4 ways, for example, as 67634176 + 212926464 = 8224^2 + 14592^2 .

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (280560649) 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 7 ways as a sum of consecutive naturals, for example, 188700 + ... + 190180.

Almost surely, 2^280560640 is an apocalyptic number.

280560640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 280560640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (345836556).

280560640 is an abundant number, since it is smaller than the sum of its proper divisors (411112472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

280560640 is a wasteful number, since it uses less digits than its factorization.

280560640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1543 (or 1525 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 280560640 is about 16749.9444775199. The cubic root of 280560640 is about 654.6496115579.

The spelling of 280560640 in words is "two hundred eighty million, five hundred sixty thousand, six hundred forty".