121557350561 has 2 divisors, whose sum is σ = 121557350562. Its totient is φ = 121557350560.

The previous prime is 121557350557. The next prime is 121557350587. The reversal of 121557350561 is 165053755121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121535904400 + 21446161 = 348620^2 + 4631^2 .

It is an emirp because it is prime and its reverse (165053755121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121557350561 - 2² = 121557350557 is a prime.

It is a super-3 number, since 3×121557350561³ (a number of 34 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (121557358561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60778675280 + 60778675281.

It is an arithmetic number, because the mean of its divisors is an integer number (60778675281).

Almost surely, 2^121557350561 is an apocalyptic number.

It is an amenable number.

121557350561 is a deficient number, since it is larger than the sum of its proper divisors (1).

121557350561 is an equidigital number, since it uses as much as digits as its factorization.

121557350561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 157500, while the sum is 41.

The spelling of 121557350561 in words is "one hundred twenty-one billion, five hundred fifty-seven million, three hundred fifty thousand, five hundred sixty-one".