121135561 has 4 divisors (see below), whose sum is σ = 121192324. Its totient is φ = 121078800.

The previous prime is 121135559. The next prime is 121135571. The reversal of 121135561 is 165531121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 165531121 = 7 ⋅23647303.

It can be written as a sum of positive squares in 2 ways, for example, as 35462025 + 85673536 = 5955^2 + 9256^2 .

It is a cyclic number.

It is not a de Polignac number, because 121135561 - 2¹ = 121135559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121135501) 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 in 3 ways as a sum of consecutive naturals, for example, 25050 + ... + 29491.

It is an arithmetic number, because the mean of its divisors is an integer number (30298081).

Almost surely, 2^121135561 is an apocalyptic number.

It is an amenable number.

121135561 is a deficient number, since it is larger than the sum of its proper divisors (56763).

121135561 is an equidigital number, since it uses as much as digits as its factorization.

121135561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56762.

The product of its digits is 900, while the sum is 25.

The square root of 121135561 is about 11006.1601387587. The cubic root of 121135561 is about 494.7933851847.

Adding to 121135561 its reverse (165531121), we get a palindrome (286666682).

The spelling of 121135561 in words is "one hundred twenty-one million, one hundred thirty-five thousand, five hundred sixty-one".