121661161 has 4 divisors (see below), whose sum is σ = 128064400. Its totient is φ = 115257924.

The previous prime is 121661117. The next prime is 121661167. The reversal of 121661161 is 161166121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 121661161 - 2¹¹ = 121659113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121661167) 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, 3201591 + ... + 3201628.

It is an arithmetic number, because the mean of its divisors is an integer number (32016100).

Almost surely, 2^121661161 is an apocalyptic number.

It is an amenable number.

121661161 is a deficient number, since it is larger than the sum of its proper divisors (6403239).

121661161 is an equidigital number, since it uses as much as digits as its factorization.

121661161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6403238.

The product of its digits is 432, while the sum is 25.

The square root of 121661161 is about 11030.0118313626. The cubic root of 121661161 is about 495.5079790165.

The spelling of 121661161 in words is "one hundred twenty-one million, six hundred sixty-one thousand, one hundred sixty-one".