195520781 has 2 divisors, whose sum is σ = 195520782. Its totient is φ = 195520780.

The previous prime is 195520747. The next prime is 195520789. The reversal of 195520781 is 187025591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 191379556 + 4141225 = 13834^2 + 2035^2 .

It is an emirp because it is prime and its reverse (187025591) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-195520781 is a prime.

It is a super-2 number, since 2×195520781² = 76456751605699922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195520789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97760390 + 97760391.

It is an arithmetic number, because the mean of its divisors is an integer number (97760391).

Almost surely, 2^195520781 is an apocalyptic number.

It is an amenable number.

195520781 is a deficient number, since it is larger than the sum of its proper divisors (1).

195520781 is an equidigital number, since it uses as much as digits as its factorization.

195520781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 38.

The square root of 195520781 is about 13982.8745614055. The cubic root of 195520781 is about 580.4047719496.

The spelling of 195520781 in words is "one hundred ninety-five million, five hundred twenty thousand, seven hundred eighty-one".