28457291 has 4 divisors (see below), whose sum is σ = 28542072. Its totient is φ = 28372512.

The previous prime is 28457267. The next prime is 28457333. The reversal of 28457291 is 19275482.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19275482 = 2 ⋅9637741.

It is a cyclic number.

It is not a de Polignac number, because 28457291 - 2⁶ = 28457227 is a prime.

It is a super-2 number, since 2×28457291² = 1619634822117362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28457791) 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, 41885 + ... + 42558.

It is an arithmetic number, because the mean of its divisors is an integer number (7135518).

Almost surely, 2^28457291 is an apocalyptic number.

28457291 is a deficient number, since it is larger than the sum of its proper divisors (84781).

28457291 is an equidigital number, since it uses as much as digits as its factorization.

28457291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84780.

The product of its digits is 40320, while the sum is 38.

The square root of 28457291 is about 5334.5375619635. The cubic root of 28457291 is about 305.3030795407.

It can be divided in two parts, 284 and 57291, that added together give a palindrome (57575).

The spelling of 28457291 in words is "twenty-eight million, four hundred fifty-seven thousand, two hundred ninety-one".