28128069 has 6 divisors (see below), whose sum is σ = 40629446. Its totient is φ = 18752040.

The previous prime is 28128059. The next prime is 28128077. The reversal of 28128069 is 96082182.

It can be written as a sum of positive squares in only one way, i.e., 24383844 + 3744225 = 4938^2 + 1935^2 .

It is a de Polignac number, because none of the positive numbers 2^k-28128069 is a prime.

It is a super-2 number, since 2×28128069² = 1582376531337522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28128019) 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 5 ways as a sum of consecutive naturals, for example, 1562662 + ... + 1562679.

Almost surely, 2^28128069 is an apocalyptic number.

It is an amenable number.

28128069 is a deficient number, since it is larger than the sum of its proper divisors (12501377).

28128069 is a wasteful number, since it uses less digits than its factorization.

28128069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3125347 (or 3125344 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 28128069 is about 5303.5901991010. The cubic root of 28128069 is about 304.1211608744.

The spelling of 28128069 in words is "twenty-eight million, one hundred twenty-eight thousand, sixty-nine".