280638 has 16 divisors (see below), whose sum is σ = 623760. Its totient is φ = 93528.

The previous prime is 280627. The next prime is 280639. The reversal of 280638 is 836082.

280638 is a `hidden beast` number, since 28 + 0 + 638 = 666.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 280638.

It is not an unprimeable number, because it can be changed into a prime (280639) 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, 2545 + ... + 2652.

It is an arithmetic number, because the mean of its divisors is an integer number (38985).

2²⁸⁰⁶³⁸ is an apocalyptic number.

280638 is an abundant number, since it is smaller than the sum of its proper divisors (343122).

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

280638 is a wasteful number, since it uses less digits than its factorization.

280638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5208 (or 5202 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 280638 is about 529.7527725270. The cubic root of 280638 is about 65.4709775664.

The spelling of 280638 in words is "two hundred eighty thousand, six hundred thirty-eight".