195643181 has 2 divisors, whose sum is σ = 195643182. Its totient is φ = 195643180.

The previous prime is 195643169. The next prime is 195643183. The reversal of 195643181 is 181346591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 112996900 + 82646281 = 10630^2 + 9091^2 .

It is an emirp because it is prime and its reverse (181346591) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-195643181 is a prime.

It is a super-2 number, since 2×195643181² = 76552508543597522, which contains 22 as substring.

Together with 195643183, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195643183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97821590 + 97821591.

It is an arithmetic number, because the mean of its divisors is an integer number (97821591).

Almost surely, 2^195643181 is an apocalyptic number.

It is an amenable number.

195643181 is a deficient number, since it is larger than the sum of its proper divisors (1).

195643181 is an equidigital number, since it uses as much as digits as its factorization.

195643181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 38.

The square root of 195643181 is about 13987.2506590824. The cubic root of 195643181 is about 580.5258617631.

The spelling of 195643181 in words is "one hundred ninety-five million, six hundred forty-three thousand, one hundred eighty-one".