2166216665 has 8 divisors (see below), whose sum is σ = 2601235968. Its totient is φ = 1731789360.

The previous prime is 2166216643. The next prime is 2166216671. The reversal of 2166216665 is 5666126612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2166216665 - 2⁶ = 2166216601 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139907 + ... + 154616.

It is an arithmetic number, because the mean of its divisors is an integer number (325154496).

Almost surely, 2^2166216665 is an apocalyptic number.

It is an amenable number.

2166216665 is a deficient number, since it is larger than the sum of its proper divisors (435019303).

2166216665 is a wasteful number, since it uses less digits than its factorization.

2166216665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295999.

The product of its digits is 155520, while the sum is 41.

The square root of 2166216665 is about 46542.6327682481. The cubic root of 2166216665 is about 1293.8997556971.

The spelling of 2166216665 in words is "two billion, one hundred sixty-six million, two hundred sixteen thousand, six hundred sixty-five".