28217611 has 4 divisors (see below), whose sum is σ = 28261872. Its totient is φ = 28173352.

The previous prime is 28217599. The next prime is 28217627. The reversal of 28217611 is 11671282.

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

It is a cyclic number.

It is not a de Polignac number, because 28217611 - 2¹⁵ = 28184843 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28217611.

It is not an unprimeable number, because it can be changed into a prime (28217011) 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, 21160 + ... + 22453.

It is an arithmetic number, because the mean of its divisors is an integer number (7065468).

Almost surely, 2^28217611 is an apocalyptic number.

28217611 is a deficient number, since it is larger than the sum of its proper divisors (44261).

28217611 is an equidigital number, since it uses as much as digits as its factorization.

28217611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44260.

The product of its digits is 1344, while the sum is 28.

The square root of 28217611 is about 5312.0251317177. The cubic root of 28217611 is about 304.4435289200.

Adding to 28217611 its reverse (11671282), we get a palindrome (39888893).

The spelling of 28217611 in words is "twenty-eight million, two hundred seventeen thousand, six hundred eleven".