121015561 has 2 divisors, whose sum is σ = 121015562. Its totient is φ = 121015560.

The previous prime is 121015547. The next prime is 121015591. The reversal of 121015561 is 165510121.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112784400 + 8231161 = 10620^2 + 2869^2 .

It is a cyclic number.

It is not a de Polignac number, because 121015561 - 2¹¹ = 121013513 is a prime.

It is not a weakly prime, because it can be changed into another prime (121015501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60507780 + 60507781.

It is an arithmetic number, because the mean of its divisors is an integer number (60507781).

Almost surely, 2^121015561 is an apocalyptic number.

It is an amenable number.

121015561 is a deficient number, since it is larger than the sum of its proper divisors (1).

121015561 is an equidigital number, since it uses as much as digits as its factorization.

121015561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 300, while the sum is 22.

The square root of 121015561 is about 11000.7072954424. The cubic root of 121015561 is about 494.6299461892.

Adding to 121015561 its reverse (165510121), we get a palindrome (286525682).

The spelling of 121015561 in words is "one hundred twenty-one million, fifteen thousand, five hundred sixty-one".