28517749 has 4 divisors (see below), whose sum is σ = 30711436. Its totient is φ = 26324064.

The previous prime is 28517707. The next prime is 28517777. The reversal of 28517749 is 94771582.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10284849 + 18232900 = 3207^2 + 4270^2 .

It is not a de Polignac number, because 28517749 - 2²³ = 20129141 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 (28527749) 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, 1096824 + ... + 1096849.

It is an arithmetic number, because the mean of its divisors is an integer number (7677859).

Almost surely, 2^28517749 is an apocalyptic number.

It is an amenable number.

28517749 is a deficient number, since it is larger than the sum of its proper divisors (2193687).

28517749 is a wasteful number, since it uses less digits than its factorization.

28517749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2193686.

The product of its digits is 141120, while the sum is 43.

The square root of 28517749 is about 5340.2012134376. The cubic root of 28517749 is about 305.5191338087.

The spelling of 28517749 in words is "twenty-eight million, five hundred seventeen thousand, seven hundred forty-nine".