2166571217 has 2 divisors, whose sum is σ = 2166571218. Its totient is φ = 2166571216.

The previous prime is 2166571201. The next prime is 2166571219. The reversal of 2166571217 is 7121756612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1824912961 + 341658256 = 42719^2 + 18484^2 .

It is a cyclic number.

It is not a de Polignac number, because 2166571217 - 2⁴ = 2166571201 is a prime.

It is a super-2 number, since 2×2166571217² = 9388061676665722178, which contains 22 as substring.

Together with 2166571219, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2166571219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1083285608 + 1083285609.

It is an arithmetic number, because the mean of its divisors is an integer number (1083285609).

Almost surely, 2^2166571217 is an apocalyptic number.

It is an amenable number.

2166571217 is a deficient number, since it is larger than the sum of its proper divisors (1).

2166571217 is an equidigital number, since it uses as much as digits as its factorization.

2166571217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35280, while the sum is 38.

The square root of 2166571217 is about 46546.4415073806. The cubic root of 2166571217 is about 1293.9703441608.

The spelling of 2166571217 in words is "two billion, one hundred sixty-six million, five hundred seventy-one thousand, two hundred seventeen".