195487781 has 2 divisors, whose sum is σ = 195487782. Its totient is φ = 195487780.

The previous prime is 195487769. The next prime is 195487837. The reversal of 195487781 is 187784591.

195487781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 188512900 + 6974881 = 13730^2 + 2641^2 .

It is an emirp because it is prime and its reverse (187784591) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-195487781 is a prime.

It is a super-2 number, since 2×195487781² = 76430945040607922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195487381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97743890 + 97743891.

It is an arithmetic number, because the mean of its divisors is an integer number (97743891).

Almost surely, 2^195487781 is an apocalyptic number.

It is an amenable number.

195487781 is a deficient number, since it is larger than the sum of its proper divisors (1).

195487781 is an equidigital number, since it uses as much as digits as its factorization.

195487781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 564480, while the sum is 50.

The square root of 195487781 is about 13981.6944967339. The cubic root of 195487781 is about 580.3721165373.

The spelling of 195487781 in words is "one hundred ninety-five million, four hundred eighty-seven thousand, seven hundred eighty-one".