28257749 has 8 divisors (see below), whose sum is σ = 30746520. Its totient is φ = 25814016.

The previous prime is 28257743. The next prime is 28257773. The reversal of 28257749 is 94775282.

It can be written as a sum of positive squares in 4 ways, for example, as 1144900 + 27112849 = 1070^2 + 5207^2 .

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 28257749 - 2¹² = 28253653 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 (28257743) 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, 9944 + ... + 12465.

It is an arithmetic number, because the mean of its divisors is an integer number (3843315).

Almost surely, 2^28257749 is an apocalyptic number.

It is an amenable number.

28257749 is a deficient number, since it is larger than the sum of its proper divisors (2488771).

28257749 is a wasteful number, since it uses less digits than its factorization.

28257749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22519.

The product of its digits is 282240, while the sum is 44.

The square root of 28257749 is about 5315.8018209862. The cubic root of 28257749 is about 304.5878119231.

The spelling of 28257749 in words is "twenty-eight million, two hundred fifty-seven thousand, seven hundred forty-nine".