121995306887989 has 2 divisors, whose sum is σ = 121995306887990. Its totient is φ = 121995306887988.

The previous prime is 121995306887963. The next prime is 121995306888001. The reversal of 121995306887989 is 989788603599121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 121916378480625 + 78928407364 = 11041575^2 + 280942^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121995306887989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121995306887959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60997653443994 + 60997653443995.

It is an arithmetic number, because the mean of its divisors is an integer number (60997653443995).

Almost surely, 2^{121995306887989} is an apocalyptic number.

It is an amenable number.

121995306887989 is a deficient number, since it is larger than the sum of its proper divisors (1).

121995306887989 is an equidigital number, since it uses as much as digits as its factorization.

121995306887989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4232632320, while the sum is 85.

The spelling of 121995306887989 in words is "one hundred twenty-one trillion, nine hundred ninety-five billion, three hundred six million, eight hundred eighty-seven thousand, nine hundred eighty-nine".