28728137 has 8 divisors (see below), whose sum is σ = 29122632. Its totient is φ = 28336000.

The previous prime is 28728121. The next prime is 28728151. The reversal of 28728137 is 73182782.

It can be written as a sum of positive squares in 4 ways, for example, as 2298256 + 26429881 = 1516^2 + 5141^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28728137 - 2⁴ = 28728121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28728137.

It is not an unprimeable number, because it can be changed into a prime (28728157) 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, 46253 + ... + 46869.

It is an arithmetic number, because the mean of its divisors is an integer number (3640329).

Almost surely, 2^28728137 is an apocalyptic number.

It is an amenable number.

28728137 is a deficient number, since it is larger than the sum of its proper divisors (394495).

28728137 is a wasteful number, since it uses less digits than its factorization.

28728137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1179.

The product of its digits is 37632, while the sum is 38.

The square root of 28728137 is about 5359.8635243819. The cubic root of 28728137 is about 306.2686101699.

The spelling of 28728137 in words is "twenty-eight million, seven hundred twenty-eight thousand, one hundred thirty-seven".