28756493 has 4 divisors (see below), whose sum is σ = 28781340. Its totient is φ = 28731648.

The previous prime is 28756477. The next prime is 28756517. The reversal of 28756493 is 39465782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39465782 = 2 ⋅19732891.

It can be written as a sum of positive squares in 2 ways, for example, as 3736489 + 25020004 = 1933^2 + 5002^2 .

It is a cyclic number.

It is not a de Polignac number, because 28756493 - 2⁴ = 28756477 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 (28756093) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10598 + ... + 13031.

It is an arithmetic number, because the mean of its divisors is an integer number (7195335).

Almost surely, 2^28756493 is an apocalyptic number.

It is an amenable number.

28756493 is a deficient number, since it is larger than the sum of its proper divisors (24847).

28756493 is a wasteful number, since it uses less digits than its factorization.

28756493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24846.

The product of its digits is 362880, while the sum is 44.

The square root of 28756493 is about 5362.5080885720. The cubic root of 28756493 is about 306.3693441289.

The spelling of 28756493 in words is "twenty-eight million, seven hundred fifty-six thousand, four hundred ninety-three".