28138 has 8 divisors (see below), whose sum is σ = 46080. Its totient is φ = 12780.

The previous prime is 28123. The next prime is 28151. The reversal of 28138 is 83182.

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

It is a Harshad number since it is a multiple of its sum of digits (22), and also a Moran number because the ratio is a prime number: 1279 = 28138 / (2 + 8 + 1 + 3 + 8).

It is a nialpdrome in base 13.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 618 + ... + 661.

It is an arithmetic number, because the mean of its divisors is an integer number (5760).

2²⁸¹³⁸ is an apocalyptic number.

28138 is a deficient number, since it is larger than the sum of its proper divisors (17942).

28138 is a wasteful number, since it uses less digits than its factorization.

28138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1292.

The product of its digits is 384, while the sum is 22.

The square root of 28138 is about 167.7438523464. The cubic root of 28138 is about 30.4156948043.

The spelling of 28138 in words is "twenty-eight thousand, one hundred thirty-eight".