121556661053 has 2 divisors, whose sum is σ = 121556661054. Its totient is φ = 121556661052.

The previous prime is 121556661047. The next prime is 121556661101. The reversal of 121556661053 is 350166655121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90590164324 + 30966496729 = 300982^2 + 175973^2 .

It is a cyclic number.

It is not a de Polignac number, because 121556661053 - 2⁶ = 121556660989 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 121556661053.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121556661013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60778330526 + 60778330527.

It is an arithmetic number, because the mean of its divisors is an integer number (60778330527).

Almost surely, 2^121556661053 is an apocalyptic number.

It is an amenable number.

121556661053 is a deficient number, since it is larger than the sum of its proper divisors (1).

121556661053 is an equidigital number, since it uses as much as digits as its factorization.

121556661053 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162000, while the sum is 41.

The spelling of 121556661053 in words is "one hundred twenty-one billion, five hundred fifty-six million, six hundred sixty-one thousand, fifty-three".