9709945781 has 2 divisors, whose sum is σ = 9709945782. Its totient is φ = 9709945780.

The previous prime is 9709945747. The next prime is 9709945823. The reversal of 9709945781 is 1875499079.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7915660900 + 1794284881 = 88970^2 + 42359^2 .

It is a cyclic number.

It is not a de Polignac number, because 9709945781 - 2⁶ = 9709945717 is a prime.

It is a super-2 number, since 2×9709945781² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 9709945781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9709945081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4854972890 + 4854972891.

It is an arithmetic number, because the mean of its divisors is an integer number (4854972891).

Almost surely, 2^9709945781 is an apocalyptic number.

It is an amenable number.

9709945781 is a deficient number, since it is larger than the sum of its proper divisors (1).

9709945781 is an equidigital number, since it uses as much as digits as its factorization.

9709945781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5715360, while the sum is 59.

The square root of 9709945781 is about 98539.0571347220. The cubic root of 9709945781 is about 2133.3998896526.

The spelling of 9709945781 in words is "nine billion, seven hundred nine million, nine hundred forty-five thousand, seven hundred eighty-one".