28687139 has 8 divisors (see below), whose sum is σ = 30976512. Its totient is φ = 26409600.

The previous prime is 28687133. The next prime is 28687163. The reversal of 28687139 is 93178682.

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

It is a cyclic number.

It is not a de Polignac number, because 28687139 - 2⁴ = 28687123 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28687139.

It is not an unprimeable number, because it can be changed into a prime (28687133) 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, 2462 + ... + 7964.

It is an arithmetic number, because the mean of its divisors is an integer number (3872064).

Almost surely, 2^28687139 is an apocalyptic number.

28687139 is a deficient number, since it is larger than the sum of its proper divisors (2289373).

28687139 is a wasteful number, since it uses less digits than its factorization.

28687139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5917.

The product of its digits is 145152, while the sum is 44.

The square root of 28687139 is about 5356.0376212271. The cubic root of 28687139 is about 306.1228485622.

The spelling of 28687139 in words is "twenty-eight million, six hundred eighty-seven thousand, one hundred thirty-nine".