28724238 has 48 divisors (see below), whose sum is σ = 66942720. Its totient is φ = 8872848.

The previous prime is 28724233. The next prime is 28724279. The reversal of 28724238 is 83242782.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28724233) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15181 + ... + 16967.

It is an arithmetic number, because the mean of its divisors is an integer number (1394640).

Almost surely, 2^28724238 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28724238, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33471360).

28724238 is an abundant number, since it is smaller than the sum of its proper divisors (38218482).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28724238 is a wasteful number, since it uses less digits than its factorization.

28724238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1861 (or 1858 counting only the distinct ones).

The product of its digits is 43008, while the sum is 36.

The square root of 28724238 is about 5359.4997900924. The cubic root of 28724238 is about 306.2547538898.

The spelling of 28724238 in words is "twenty-eight million, seven hundred twenty-four thousand, two hundred thirty-eight".