121555364209 has 2 divisors, whose sum is σ = 121555364210. Its totient is φ = 121555364208.

The previous prime is 121555364191. The next prime is 121555364237. The reversal of 121555364209 is 902463555121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 118523209984 + 3032154225 = 344272^2 + 55065^2 .

It is a cyclic number.

It is not a de Polignac number, because 121555364209 - 2⁷ = 121555364081 is a prime.

It is not a weakly prime, because it can be changed into another prime (121555365209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60777682104 + 60777682105.

It is an arithmetic number, because the mean of its divisors is an integer number (60777682105).

Almost surely, 2^121555364209 is an apocalyptic number.

It is an amenable number.

121555364209 is a deficient number, since it is larger than the sum of its proper divisors (1).

121555364209 is an equidigital number, since it uses as much as digits as its factorization.

121555364209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324000, while the sum is 43.

The spelling of 121555364209 in words is "one hundred twenty-one billion, five hundred fifty-five million, three hundred sixty-four thousand, two hundred nine".