121641505991 has 2 divisors, whose sum is σ = 121641505992. Its totient is φ = 121641505990.

The previous prime is 121641505963. The next prime is 121641506009. The reversal of 121641505991 is 199505146121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121641505991 - 2²⁶ = 121574397127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121641505091) 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, 60820752995 + 60820752996.

It is an arithmetic number, because the mean of its divisors is an integer number (60820752996).

Almost surely, 2^121641505991 is an apocalyptic number.

121641505991 is a deficient number, since it is larger than the sum of its proper divisors (1).

121641505991 is an equidigital number, since it uses as much as digits as its factorization.

121641505991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 97200, while the sum is 44.

The spelling of 121641505991 in words is "one hundred twenty-one billion, six hundred forty-one million, five hundred five thousand, nine hundred ninety-one".