121310561 has 2 divisors, whose sum is σ = 121310562. Its totient is φ = 121310560.

The previous prime is 121310551. The next prime is 121310633. The reversal of 121310561 is 165013121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 117310561 + 4000000 = 10831^2 + 2000^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121310561 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (121310551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60655280 + 60655281.

It is an arithmetic number, because the mean of its divisors is an integer number (60655281).

Almost surely, 2^121310561 is an apocalyptic number.

It is an amenable number.

121310561 is a deficient number, since it is larger than the sum of its proper divisors (1).

121310561 is an equidigital number, since it uses as much as digits as its factorization.

121310561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 121310561 is about 11014.1073628325. The cubic root of 121310561 is about 495.0315403499.

Adding to 121310561 its reverse (165013121), we get a palindrome (286323682).

The spelling of 121310561 in words is "one hundred twenty-one million, three hundred ten thousand, five hundred sixty-one".