121635665 has 4 divisors (see below), whose sum is σ = 145962804. Its totient is φ = 97308528.

The previous prime is 121635641. The next prime is 121635713. The reversal of 121635665 is 566536121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 91087936 + 30547729 = 9544^2 + 5527^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121635665 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, 12163562 + ... + 12163571.

It is an arithmetic number, because the mean of its divisors is an integer number (36490701).

Almost surely, 2^121635665 is an apocalyptic number.

It is an amenable number.

121635665 is a deficient number, since it is larger than the sum of its proper divisors (24327139).

121635665 is an equidigital number, since it uses as much as digits as its factorization.

121635665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24327138.

The product of its digits is 32400, while the sum is 35.

The square root of 121635665 is about 11028.8560150181. The cubic root of 121635665 is about 495.4733627814.

The spelling of 121635665 in words is "one hundred twenty-one million, six hundred thirty-five thousand, six hundred sixty-five".