28257538 has 4 divisors (see below), whose sum is σ = 42386310. Its totient is φ = 14128768.

The previous prime is 28257527. The next prime is 28257557. The reversal of 28257538 is 83575282.

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

It can be written as a sum of positive squares in only one way, i.e., 26904969 + 1352569 = 5187^2 + 1163^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 28257538.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7064383 + ... + 7064386.

Almost surely, 2^28257538 is an apocalyptic number.

28257538 is a deficient number, since it is larger than the sum of its proper divisors (14128772).

28257538 is a wasteful number, since it uses less digits than its factorization.

28257538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14128771.

The product of its digits is 134400, while the sum is 40.

The square root of 28257538 is about 5315.7819744606. The cubic root of 28257538 is about 304.5870538043.

It can be divided in two parts, 2825753 and 8, that added together give a 4-th power (2825761 = 41⁴).

The spelling of 28257538 in words is "twenty-eight million, two hundred fifty-seven thousand, five hundred thirty-eight".