121306561 has 2 divisors, whose sum is σ = 121306562. Its totient is φ = 121306560.

The previous prime is 121306487. The next prime is 121306573. The reversal of 121306561 is 165603121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113550336 + 7756225 = 10656^2 + 2785^2 .

It is an emirp because it is prime and its reverse (165603121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121306561 - 2¹⁷ = 121175489 is a prime.

It is not a weakly prime, because it can be changed into another prime (121306961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60653280 + 60653281.

It is an arithmetic number, because the mean of its divisors is an integer number (60653281).

Almost surely, 2^121306561 is an apocalyptic number.

It is an amenable number.

121306561 is a deficient number, since it is larger than the sum of its proper divisors (1).

121306561 is an equidigital number, since it uses as much as digits as its factorization.

121306561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 121306561 is about 11013.9257760346. The cubic root of 121306561 is about 495.0260993619.

Adding to 121306561 its reverse (165603121), we get a palindrome (286909682).

The spelling of 121306561 in words is "one hundred twenty-one million, three hundred six thousand, five hundred sixty-one".