28123213 has 2 divisors, whose sum is σ = 28123214. Its totient is φ = 28123212.

The previous prime is 28123201. The next prime is 28123229. The reversal of 28123213 is 31232182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27741289 + 381924 = 5267^2 + 618^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28123213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28123283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14061606 + 14061607.

It is an arithmetic number, because the mean of its divisors is an integer number (14061607).

Almost surely, 2^28123213 is an apocalyptic number.

It is an amenable number.

28123213 is a deficient number, since it is larger than the sum of its proper divisors (1).

28123213 is an equidigital number, since it uses as much as digits as its factorization.

28123213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 22.

The square root of 28123213 is about 5303.1323762471. The cubic root of 28123213 is about 304.1036588156.

Adding to 28123213 its reverse (31232182), we get a palindrome (59355395).

The spelling of 28123213 in words is "twenty-eight million, one hundred twenty-three thousand, two hundred thirteen".