28138536 has 128 divisors (see below), whose sum is σ = 84672000. Its totient is φ = 8626176.

The previous prime is 28138531. The next prime is 28138543. The reversal of 28138536 is 63583182.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 28138536.

It is not an unprimeable number, because it can be changed into a prime (28138531) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 290040 + ... + 290136.

It is an arithmetic number, because the mean of its divisors is an integer number (661500).

Almost surely, 2^28138536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28138536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42336000).

28138536 is an abundant number, since it is smaller than the sum of its proper divisors (56533464).

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

28138536 is a wasteful number, since it uses less digits than its factorization.

28138536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208 (or 198 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 28138536 is about 5304.5768917040. The cubic root of 28138536 is about 304.1588793236.

The spelling of 28138536 in words is "twenty-eight million, one hundred thirty-eight thousand, five hundred thirty-six".