28138589 has 4 divisors (see below), whose sum is σ = 28150080. Its totient is φ = 28127100.

The previous prime is 28138573. The next prime is 28138597. The reversal of 28138589 is 98583182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 98583182 = 2 ⋅49291591.

It is a cyclic number.

It is not a de Polignac number, because 28138589 - 2⁴ = 28138573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28138529) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 437 + ... + 7514.

It is an arithmetic number, because the mean of its divisors is an integer number (7037520).

Almost surely, 2^28138589 is an apocalyptic number.

It is an amenable number.

28138589 is a deficient number, since it is larger than the sum of its proper divisors (11491).

28138589 is an equidigital number, since it uses as much as digits as its factorization.

28138589 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11490.

The product of its digits is 138240, while the sum is 44.

The square root of 28138589 is about 5304.5818873875. The cubic root of 28138589 is about 304.1590702884.

The spelling of 28138589 in words is "twenty-eight million, one hundred thirty-eight thousand, five hundred eighty-nine".