121565721029 has 2 divisors, whose sum is σ = 121565721030. Its totient is φ = 121565721028.

The previous prime is 121565721023. The next prime is 121565721061. The reversal of 121565721029 is 920127565121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78248872900 + 43316848129 = 279730^2 + 208127^2 .

It is an emirp because it is prime and its reverse (920127565121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121565721029 - 2³⁶ = 52846244293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121565721023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60782860514 + 60782860515.

It is an arithmetic number, because the mean of its divisors is an integer number (60782860515).

Almost surely, 2^121565721029 is an apocalyptic number.

It is an amenable number.

121565721029 is a deficient number, since it is larger than the sum of its proper divisors (1).

121565721029 is an equidigital number, since it uses as much as digits as its factorization.

121565721029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 75600, while the sum is 41.

The spelling of 121565721029 in words is "one hundred twenty-one billion, five hundred sixty-five million, seven hundred twenty-one thousand, twenty-nine".