28728817 has 24 divisors (see below), whose sum is σ = 34257600. Its totient is φ = 23969088.

The previous prime is 28728787. The next prime is 28728851. The reversal of 28728817 is 71882782.

It is not a de Polignac number, because 28728817 - 2¹¹ = 28726769 is a prime.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28728857) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 73659 + ... + 74047.

It is an arithmetic number, because the mean of its divisors is an integer number (1427400).

Almost surely, 2^28728817 is an apocalyptic number.

It is an amenable number.

28728817 is a deficient number, since it is larger than the sum of its proper divisors (5528783).

28728817 is a wasteful number, since it uses less digits than its factorization.

28728817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457 (or 444 counting only the distinct ones).

The product of its digits is 100352, while the sum is 43.

The square root of 28728817 is about 5359.9269584575. The cubic root of 28728817 is about 306.2710266279.

The spelling of 28728817 in words is "twenty-eight million, seven hundred twenty-eight thousand, eight hundred seventeen".