28158238 has 4 divisors (see below), whose sum is σ = 42237360. Its totient is φ = 14079118.

The previous prime is 28158191. The next prime is 28158257. The reversal of 28158238 is 83285182.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 28158197 and 28158206.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7039558 + ... + 7039561.

It is an arithmetic number, because the mean of its divisors is an integer number (10559340).

Almost surely, 2^28158238 is an apocalyptic number.

28158238 is a deficient number, since it is larger than the sum of its proper divisors (14079122).

28158238 is a wasteful number, since it uses less digits than its factorization.

28158238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14079121.

The product of its digits is 30720, while the sum is 37.

The square root of 28158238 is about 5306.4336422874. The cubic root of 28158238 is about 304.2298512719.

The spelling of 28158238 in words is "twenty-eight million, one hundred fifty-eight thousand, two hundred thirty-eight".