28040217 has 4 divisors (see below), whose sum is σ = 37386960. Its totient is φ = 18693476.

The previous prime is 28040209. The next prime is 28040227. The reversal of 28040217 is 71204082.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28040217 - 2³ = 28040209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28040227) 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, 4673367 + ... + 4673372.

It is an arithmetic number, because the mean of its divisors is an integer number (9346740).

Almost surely, 2^28040217 is an apocalyptic number.

It is an amenable number.

28040217 is a deficient number, since it is larger than the sum of its proper divisors (9346743).

28040217 is an equidigital number, since it uses as much as digits as its factorization.

28040217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9346742.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 28040217 is about 5295.3014078521. The cubic root of 28040217 is about 303.8042115640.

Adding to 28040217 its reverse (71204082), we get a palindrome (99244299).

The spelling of 28040217 in words is "twenty-eight million, forty thousand, two hundred seventeen".