121818121 has 2 divisors, whose sum is σ = 121818122. Its totient is φ = 121818120.

The previous prime is 121818119. The next prime is 121818133.

121818121 is nontrivially palindromic in base 10.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119683600 + 2134521 = 10940^2 + 1461^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 121818121 - 2¹ = 121818119 is a prime.

Together with 121818119, it forms a pair of twin primes.

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 (121818721) 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, 60909060 + 60909061.

It is an arithmetic number, because the mean of its divisors is an integer number (60909061).

Almost surely, 2^121818121 is an apocalyptic number.

It is an amenable number.

121818121 is a deficient number, since it is larger than the sum of its proper divisors (1).

121818121 is an equidigital number, since it uses as much as digits as its factorization.

121818121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 256, while the sum is 25.

The square root of 121818121 is about 11037.1246708552. The cubic root of 121818121 is about 495.7209790921.

It can be divided in two parts, 12181 and 8121, that added together give a palindrome (20302).

The spelling of 121818121 in words is "one hundred twenty-one million, eight hundred eighteen thousand, one hundred twenty-one".