28685213 has 2 divisors, whose sum is σ = 28685214. Its totient is φ = 28685212.

The previous prime is 28685183. The next prime is 28685219. The reversal of 28685213 is 31258682.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28494244 + 190969 = 5338^2 + 437^2 .

It is a cyclic number.

It is not a de Polignac number, because 28685213 - 2⁶ = 28685149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28685219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14342606 + 14342607.

It is an arithmetic number, because the mean of its divisors is an integer number (14342607).

Almost surely, 2^28685213 is an apocalyptic number.

It is an amenable number.

28685213 is a deficient number, since it is larger than the sum of its proper divisors (1).

28685213 is an equidigital number, since it uses as much as digits as its factorization.

28685213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23040, while the sum is 35.

The square root of 28685213 is about 5355.8578211151. The cubic root of 28685213 is about 306.1159975734.

The spelling of 28685213 in words is "twenty-eight million, six hundred eighty-five thousand, two hundred thirteen".