280123305 has 64 divisors (see below), whose sum is σ = 561420288. Its totient is φ = 115868160.

The previous prime is 280123273. The next prime is 280123307. The reversal of 280123305 is 503321082.

It is not a de Polignac number, because 280123305 - 2⁵ = 280123273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (280123307) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 326437 + ... + 327293.

It is an arithmetic number, because the mean of its divisors is an integer number (8772192).

Almost surely, 2^280123305 is an apocalyptic number.

It is an amenable number.

280123305 is an abundant number, since it is smaller than the sum of its proper divisors (281296983).

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

280123305 is a wasteful number, since it uses less digits than its factorization.

280123305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 280123305 is about 16736.8845667287. The cubic root of 280123305 is about 654.3092809994.

Adding to 280123305 its reverse (503321082), we get a palindrome (783444387).

It can be divided in two parts, 2801 and 23305, that added together give a triangular number (26106 = T₂₂₈).

The spelling of 280123305 in words is "two hundred eighty million, one hundred twenty-three thousand, three hundred five".