2161020217 has 2 divisors, whose sum is σ = 2161020218. Its totient is φ = 2161020216.

The previous prime is 2161020203. The next prime is 2161020293. The reversal of 2161020217 is 7120201612.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2145171856 + 15848361 = 46316^2 + 3981^2 .

It is a cyclic number.

It is not a de Polignac number, because 2161020217 - 2⁷ = 2161020089 is a prime.

It is not a weakly prime, because it can be changed into another prime (2161020817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080510108 + 1080510109.

It is an arithmetic number, because the mean of its divisors is an integer number (1080510109).

Almost surely, 2^2161020217 is an apocalyptic number.

It is an amenable number.

2161020217 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161020217 is an equidigital number, since it uses as much as digits as its factorization.

2161020217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 2161020217 is about 46486.7746461292. The cubic root of 2161020217 is about 1292.8642996611.

Adding to 2161020217 its reverse (7120201612), we get a palindrome (9281221829).

The spelling of 2161020217 in words is "two billion, one hundred sixty-one million, twenty thousand, two hundred seventeen".