28218605 has 8 divisors (see below), whose sum is σ = 34777752. Its totient is φ = 21964608.

The previous prime is 28218599. The next prime is 28218611. The reversal of 28218605 is 50681282.

It is an interprime number because it is at equal distance from previous prime (28218599) and next prime (28218611).

It can be written as a sum of positive squares in 4 ways, for example, as 11095561 + 17123044 = 3331^2 + 4138^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28218605 - 2⁸ = 28218349 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76082 + ... + 76451.

It is an arithmetic number, because the mean of its divisors is an integer number (4347219).

Almost surely, 2^28218605 is an apocalyptic number.

It is an amenable number.

28218605 is a deficient number, since it is larger than the sum of its proper divisors (6559147).

28218605 is a wasteful number, since it uses less digits than its factorization.

28218605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152575.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 28218605 is about 5312.1186921981. The cubic root of 28218605 is about 304.4471036771.

Adding to 28218605 its reverse (50681282), we get a palindrome (78899887).

The spelling of 28218605 in words is "twenty-eight million, two hundred eighteen thousand, six hundred five".