287639 has 8 divisors (see below), whose sum is σ = 318720. Its totient is φ = 257400.

The previous prime is 287629. The next prime is 287669. The reversal of 287639 is 936782.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 287639 - 2⁸ = 287383 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 287599 and 287608.

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 287639.

It is not an unprimeable number, because it can be changed into a prime (287629) 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, 704 + ... + 1034.

It is an arithmetic number, because the mean of its divisors is an integer number (39840).

2²⁸⁷⁶³⁹ is an apocalyptic number.

287639 is a deficient number, since it is larger than the sum of its proper divisors (31081).

287639 is a wasteful number, since it uses less digits than its factorization.

287639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421.

The product of its digits is 18144, while the sum is 35.

The square root of 287639 is about 536.3198672434. The cubic root of 287639 is about 66.0109409471.

It can be divided in two parts, 28 and 7639, that added together give a palindrome (7667).

The spelling of 287639 in words is "two hundred eighty-seven thousand, six hundred thirty-nine".