105728209 has 2 divisors, whose sum is σ = 105728210. Its totient is φ = 105728208.

The previous prime is 105728167. The next prime is 105728221. The reversal of 105728209 is 902827501.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 94031809 + 11696400 = 9697^2 + 3420^2 .

It is an emirp because it is prime and its reverse (902827501) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 105728209 - 2⁷ = 105728081 is a prime.

It is a super-2 number, since 2×105728209² = 22356908356695362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (105728279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52864104 + 52864105.

It is an arithmetic number, because the mean of its divisors is an integer number (52864105).

Almost surely, 2^105728209 is an apocalyptic number.

It is an amenable number.

105728209 is a deficient number, since it is larger than the sum of its proper divisors (1).

105728209 is an equidigital number, since it uses as much as digits as its factorization.

105728209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 105728209 is about 10282.4223313381. The cubic root of 105728209 is about 472.8575109362.

It can be divided in two parts, 10572 and 8209, that added together give a palindrome (18781).

The spelling of 105728209 in words is "one hundred five million, seven hundred twenty-eight thousand, two hundred nine".