166001201321 has 2 divisors, whose sum is σ = 166001201322. Its totient is φ = 166001201320.

The previous prime is 166001201273. The next prime is 166001201323. The reversal of 166001201321 is 123102100661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158355447721 + 7645753600 = 397939^2 + 87440^2 .

It is a cyclic number.

It is not a de Polignac number, because 166001201321 - 2¹⁰ = 166001200297 is a prime.

It is a Sophie Germain prime.

Together with 166001201323, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (166001201323) by changing a digit.

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 as a sum of consecutive naturals, namely, 83000600660 + 83000600661.

It is an arithmetic number, because the mean of its divisors is an integer number (83000600661).

Almost surely, 2^166001201321 is an apocalyptic number.

It is an amenable number.

166001201321 is a deficient number, since it is larger than the sum of its proper divisors (1).

166001201321 is an equidigital number, since it uses as much as digits as its factorization.

166001201321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

Adding to 166001201321 its reverse (123102100661), we get a palindrome (289103301982).

The spelling of 166001201321 in words is "one hundred sixty-six billion, one million, two hundred one thousand, three hundred twenty-one".