121557707549 has 2 divisors, whose sum is σ = 121557707550. Its totient is φ = 121557707548.

The previous prime is 121557707497. The next prime is 121557707587. The reversal of 121557707549 is 945707755121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 94120104100 + 27437603449 = 306790^2 + 165643^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121557707549 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121557707549.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121557707149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60778853774 + 60778853775.

It is an arithmetic number, because the mean of its divisors is an integer number (60778853775).

Almost surely, 2^121557707549 is an apocalyptic number.

It is an amenable number.

121557707549 is a deficient number, since it is larger than the sum of its proper divisors (1).

121557707549 is an equidigital number, since it uses as much as digits as its factorization.

121557707549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3087000, while the sum is 53.

The spelling of 121557707549 in words is "one hundred twenty-one billion, five hundred fifty-seven million, seven hundred seven thousand, five hundred forty-nine".