121136561 has 32 divisors (see below), whose sum is σ = 160677888. Its totient is φ = 88672320.

The previous prime is 121136551. The next prime is 121136563. The reversal of 121136561 is 165631121.

It is a cyclic number.

It is not a de Polignac number, because 121136561 - 2¹⁴ = 121120177 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121136561.

It is not an unprimeable number, because it can be changed into a prime (121136563) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 63950 + ... + 65816.

It is an arithmetic number, because the mean of its divisors is an integer number (5021184).

Almost surely, 2^121136561 is an apocalyptic number.

It is an amenable number.

121136561 is a deficient number, since it is larger than the sum of its proper divisors (39541327).

121136561 is a wasteful number, since it uses less digits than its factorization.

121136561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1941.

The product of its digits is 1080, while the sum is 26.

The square root of 121136561 is about 11006.2055677695. The cubic root of 121136561 is about 494.7947467227.

Adding to 121136561 its reverse (165631121), we get a palindrome (286767682).

The spelling of 121136561 in words is "one hundred twenty-one million, one hundred thirty-six thousand, five hundred sixty-one".