2166721117 has 8 divisors (see below), whose sum is σ = 2364317280. Its totient is φ = 1969228560.

The previous prime is 2166721093. The next prime is 2166721127. The reversal of 2166721117 is 7111276612.

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

It is a cyclic number.

It is not a de Polignac number, because 2166721117 - 2¹¹ = 2166719069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166721127) 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 7 ways as a sum of consecutive naturals, for example, 21634 + ... + 69292.

It is an arithmetic number, because the mean of its divisors is an integer number (295539660).

Almost surely, 2^2166721117 is an apocalyptic number.

It is an amenable number.

2166721117 is a deficient number, since it is larger than the sum of its proper divisors (197596163).

2166721117 is a wasteful number, since it uses less digits than its factorization.

2166721117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51803.

The product of its digits is 7056, while the sum is 34.

The square root of 2166721117 is about 46548.0516992924. The cubic root of 2166721117 is about 1294.0001857342. Note that the first 3 decimals are identical.

Adding to 2166721117 its reverse (7111276612), we get a palindrome (9277997729).

The spelling of 2166721117 in words is "two billion, one hundred sixty-six million, seven hundred twenty-one thousand, one hundred seventeen".