28138938 has 16 divisors (see below), whose sum is σ = 56413056. Its totient is φ = 9357120.

The previous prime is 28138937. The next prime is 28138949. The reversal of 28138938 is 83983182.

It is a self number, because there is not a number n which added to its sum of digits gives 28138938.

It is not an unprimeable number, because it can be changed into a prime (28138937) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2818 + ... + 8013.

It is an arithmetic number, because the mean of its divisors is an integer number (3525816).

Almost surely, 2^28138938 is an apocalyptic number.

28138938 is an abundant number, since it is smaller than the sum of its proper divisors (28274118).

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

28138938 is a wasteful number, since it uses less digits than its factorization.

28138938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11269.

The product of its digits is 82944, while the sum is 42.

The square root of 28138938 is about 5304.6147833749. The cubic root of 28138938 is about 304.1603277676.

The spelling of 28138938 in words is "twenty-eight million, one hundred thirty-eight thousand, nine hundred thirty-eight".