123612121 has 2 divisors, whose sum is σ = 123612122. Its totient is φ = 123612120.

The previous prime is 123612103. The next prime is 123612127. The reversal of 123612121 is 121216321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69956496 + 53655625 = 8364^2 + 7325^2 .

It is an emirp because it is prime and its reverse (121216321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 123612121 - 2¹⁷ = 123481049 is a 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 (123612127) 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, 61806060 + 61806061.

It is an arithmetic number, because the mean of its divisors is an integer number (61806061).

Almost surely, 2^123612121 is an apocalyptic number.

It is an amenable number.

123612121 is a deficient number, since it is larger than the sum of its proper divisors (1).

123612121 is an equidigital number, since it uses as much as digits as its factorization.

123612121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 19.

The square root of 123612121 is about 11118.0988033027. The cubic root of 123612121 is about 498.1426033660.

Adding to 123612121 its reverse (121216321), we get a palindrome (244828442).

The spelling of 123612121 in words is "one hundred twenty-three million, six hundred twelve thousand, one hundred twenty-one".