28240997 has 4 divisors (see below), whose sum is σ = 28773900. Its totient is φ = 27708096.

The previous prime is 28240991. The next prime is 28241021. The reversal of 28240997 is 79904282.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79904282 = 2 ⋅39952141.

It can be written as a sum of positive squares in 2 ways, for example, as 20124196 + 8116801 = 4486^2 + 2849^2 .

It is a cyclic number.

It is not a de Polignac number, because 28240997 - 2¹⁰ = 28239973 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 (28240991) 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, 266372 + ... + 266477.

It is an arithmetic number, because the mean of its divisors is an integer number (7193475).

Almost surely, 2^28240997 is an apocalyptic number.

It is an amenable number.

28240997 is a deficient number, since it is larger than the sum of its proper divisors (532903).

28240997 is an equidigital number, since it uses as much as digits as its factorization.

28240997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532902.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 28240997 is about 5314.2259078816. The cubic root of 28240997 is about 304.5276105762.

The spelling of 28240997 in words is "twenty-eight million, two hundred forty thousand, nine hundred ninety-seven".