181818121 has 2 divisors, whose sum is σ = 181818122. Its totient is φ = 181818120.

The previous prime is 181818083. The next prime is 181818173. The reversal of 181818121 is 121818181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 167340096 + 14478025 = 12936^2 + 3805^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-181818121 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (181828121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90909060 + 90909061.

It is an arithmetic number, because the mean of its divisors is an integer number (90909061).

Almost surely, 2^181818121 is an apocalyptic number.

It is an amenable number.

181818121 is a deficient number, since it is larger than the sum of its proper divisors (1).

181818121 is an equidigital number, since it uses as much as digits as its factorization.

181818121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1024, while the sum is 31.

The square root of 181818121 is about 13483.9949940661. The cubic root of 181818121 is about 566.5162717761.

The spelling of 181818121 in words is "one hundred eighty-one million, eight hundred eighteen thousand, one hundred twenty-one".