280639 has 2 divisors, whose sum is σ = 280640. Its totient is φ = 280638.

The previous prime is 280627. The next prime is 280673. The reversal of 280639 is 936082.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 280639 - 2⁵ = 280607 is a prime.

280639 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (280699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140319 + 140320.

It is an arithmetic number, because the mean of its divisors is an integer number (140320).

2²⁸⁰⁶³⁹ is an apocalyptic number.

280639 is a deficient number, since it is larger than the sum of its proper divisors (1).

280639 is an equidigital number, since it uses as much as digits as its factorization.

280639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 280639 is about 529.7537163626. The cubic root of 280639 is about 65.4710553307.

It can be divided in two parts, 280 and 639, that added together give a palindrome (919).

The spelling of 280639 in words is "two hundred eighty thousand, six hundred thirty-nine".