28217213 has 2 divisors, whose sum is σ = 28217214. Its totient is φ = 28217212.

The previous prime is 28217209. The next prime is 28217221. The reversal of 28217213 is 31271282.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24970009 + 3247204 = 4997^2 + 1802^2 .

It is a cyclic number.

It is not a de Polignac number, because 28217213 - 2² = 28217209 is a prime.

It is a super-2 number, since 2×28217213² = 1592422218974738, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28217243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14108606 + 14108607.

It is an arithmetic number, because the mean of its divisors is an integer number (14108607).

Almost surely, 2^28217213 is an apocalyptic number.

It is an amenable number.

28217213 is a deficient number, since it is larger than the sum of its proper divisors (1).

28217213 is an equidigital number, since it uses as much as digits as its factorization.

28217213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1344, while the sum is 26.

The square root of 28217213 is about 5311.9876694134. The cubic root of 28217213 is about 304.4420975551.

Adding to 28217213 its reverse (31271282), we get a palindrome (59488495).

The spelling of 28217213 in words is "twenty-eight million, two hundred seventeen thousand, two hundred thirteen".