121878121 has 2 divisors, whose sum is σ = 121878122. Its totient is φ = 121878120.

The previous prime is 121878089. The next prime is 121878139.

121878121 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116402521 + 5475600 = 10789^2 + 2340^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 121878121 - 2⁵ = 121878089 is a prime.

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

It is a zygodrome in base 3.

It is not a weakly prime, because it can be changed into another prime (121878161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60939060 + 60939061.

It is an arithmetic number, because the mean of its divisors is an integer number (60939061).

Almost surely, 2^121878121 is an apocalyptic number.

It is an amenable number.

121878121 is a deficient number, since it is larger than the sum of its proper divisors (1).

121878121 is an equidigital number, since it uses as much as digits as its factorization.

121878121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1792, while the sum is 31.

The square root of 121878121 is about 11039.8424354698. The cubic root of 121878121 is about 495.8023528007.

The spelling of 121878121 in words is "one hundred twenty-one million, eight hundred seventy-eight thousand, one hundred twenty-one".