11818181 has 2 divisors, whose sum is σ = 11818182. Its totient is φ = 11818180.

The previous prime is 11818151. The next prime is 11818199. The reversal of 11818181 is 18181811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8755681 + 3062500 = 2959^2 + 1750^2 .

It is a cyclic number.

It is not a de Polignac number, because 11818181 - 2¹⁸ = 11556037 is a prime.

It is a super-2 number, since 2×11818181² = 279338804297522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11818141) 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, 5909090 + 5909091.

It is an arithmetic number, because the mean of its divisors is an integer number (5909091).

Almost surely, 2^11818181 is an apocalyptic number.

It is an amenable number.

11818181 is a deficient number, since it is larger than the sum of its proper divisors (1).

11818181 is an equidigital number, since it uses as much as digits as its factorization.

11818181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 512, while the sum is 29.

The square root of 11818181 is about 3437.7581357623. The cubic root of 11818181 is about 227.7806768001.

Adding to 11818181 its reverse (18181811), we get a palindrome (29999992).

The spelling of 11818181 in words is "eleven million, eight hundred eighteen thousand, one hundred eighty-one".