2166511217 has 12 divisors (see below), whose sum is σ = 2403212364. Its totient is φ = 1951073280.

The previous prime is 2166511189. The next prime is 2166511261. The reversal of 2166511217 is 7121156612.

It can be written as a sum of positive squares in 6 ways, for example, as 1093228096 + 1073283121 = 33064^2 + 32761^2 .

It is not a de Polignac number, because 2166511217 - 2⁶ = 2166511153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2166511117) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 149408 + ... + 163265.

It is an arithmetic number, because the mean of its divisors is an integer number (200267697).

Almost surely, 2^2166511217 is an apocalyptic number.

It is an amenable number.

2166511217 is a deficient number, since it is larger than the sum of its proper divisors (236701147).

2166511217 is a wasteful number, since it uses less digits than its factorization.

2166511217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312740 (or 312727 counting only the distinct ones).

The product of its digits is 5040, while the sum is 32.

The square root of 2166511217 is about 46545.7969853348. The cubic root of 2166511217 is about 1293.9583991827.

Adding to 2166511217 its reverse (7121156612), we get a palindrome (9287667829).

The spelling of 2166511217 in words is "two billion, one hundred sixty-six million, five hundred eleven thousand, two hundred seventeen".