28007213 has 8 divisors (see below), whose sum is σ = 30217656. Its totient is φ = 25804800.

The previous prime is 28007209. The next prime is 28007219. The reversal of 28007213 is 31270082.

It can be written as a sum of positive squares in 4 ways, for example, as 7963684 + 20043529 = 2822^2 + 4477^2 .

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 28007213 - 2² = 28007209 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 (28007219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6653 + ... + 10013.

It is an arithmetic number, because the mean of its divisors is an integer number (3777207).

Almost surely, 2^28007213 is an apocalyptic number.

It is an amenable number.

28007213 is a deficient number, since it is larger than the sum of its proper divisors (2210443).

28007213 is a wasteful number, since it uses less digits than its factorization.

28007213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4015.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 28007213 is about 5292.1841426768. The cubic root of 28007213 is about 303.6849698492.

Adding to 28007213 its reverse (31270082), we get a palindrome (59277295).

The spelling of 28007213 in words is "twenty-eight million, seven thousand, two hundred thirteen".