121161665 has 4 divisors (see below), whose sum is σ = 145394004. Its totient is φ = 96929328.

The previous prime is 121161647. The next prime is 121161697. The reversal of 121161665 is 566161121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 566161121 = 4079 ⋅138799.

It can be written as a sum of positive squares in 2 ways, for example, as 80928016 + 40233649 = 8996^2 + 6343^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121161665 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12116162 + ... + 12116171.

It is an arithmetic number, because the mean of its divisors is an integer number (36348501).

Almost surely, 2^121161665 is an apocalyptic number.

It is an amenable number.

121161665 is a deficient number, since it is larger than the sum of its proper divisors (24232339).

121161665 is an equidigital number, since it uses as much as digits as its factorization.

121161665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24232338.

The product of its digits is 2160, while the sum is 29.

The square root of 121161665 is about 11007.3459562240. The cubic root of 121161665 is about 494.8289243188.

The spelling of 121161665 in words is "one hundred twenty-one million, one hundred sixty-one thousand, six hundred sixty-five".