28128773 has 4 divisors (see below), whose sum is σ = 28157088. Its totient is φ = 28100460.

The previous prime is 28128719. The next prime is 28128787. The reversal of 28128773 is 37782182.

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 an emirpimes, since its reverse is a distinct semiprime: 37782182 = 2 ⋅18891091.

It is a cyclic number.

It is not a de Polignac number, because 28128773 - 2¹⁴ = 28112389 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28128973) 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, 12611 + ... + 14672.

It is an arithmetic number, because the mean of its divisors is an integer number (7039272).

Almost surely, 2^28128773 is an apocalyptic number.

It is an amenable number.

28128773 is a deficient number, since it is larger than the sum of its proper divisors (28315).

28128773 is a wasteful number, since it uses less digits than its factorization.

28128773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28314.

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

The square root of 28128773 is about 5303.6565688212. The cubic root of 28128773 is about 304.1236980732.

The spelling of 28128773 in words is "twenty-eight million, one hundred twenty-eight thousand, seven hundred seventy-three".