28140138 has 48 divisors (see below), whose sum is σ = 66928680. Its totient is φ = 8491392.

The previous prime is 28140137. The next prime is 28140139. The reversal of 28140138 is 83104182.

It is an interprime number because it is at equal distance from previous prime (28140137) and next prime (28140139).

It can be written as a sum of positive squares in 4 ways, for example, as 14722569 + 13417569 = 3837^2 + 3663^2 .

It is not an unprimeable number, because it can be changed into a prime (28140131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11268 + ... + 13536.

Almost surely, 2^28140138 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28140138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33464340).

28140138 is an abundant number, since it is smaller than the sum of its proper divisors (38788542).

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

28140138 is a wasteful number, since it uses less digits than its factorization.

28140138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2343 (or 2340 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 28140138 is about 5304.7278912306. The cubic root of 28140138 is about 304.1646513993.

The spelling of 28140138 in words is "twenty-eight million, one hundred forty thousand, one hundred thirty-eight".