195781 has 2 divisors, whose sum is σ = 195782. Its totient is φ = 195780.

The previous prime is 195761. The next prime is 195787. The reversal of 195781 is 187591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152100 + 43681 = 390^2 + 209^2 .

It is a cyclic number.

It is not a de Polignac number, because 195781 - 2¹⁷ = 64709 is a prime.

It is a super-2 number, since 2×195781² = 76660399922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97890 + 97891.

It is an arithmetic number, because the mean of its divisors is an integer number (97891).

2¹⁹⁵⁷⁸¹ is an apocalyptic number.

It is an amenable number.

195781 is a deficient number, since it is larger than the sum of its proper divisors (1).

195781 is an equidigital number, since it uses as much as digits as its factorization.

195781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2520, while the sum is 31.

The square root of 195781 is about 442.4714680067. The cubic root of 195781 is about 58.0662145096.

The spelling of 195781 in words is "one hundred ninety-five thousand, seven hundred eighty-one".