9991801709 has 2 divisors, whose sum is σ = 9991801710. Its totient is φ = 9991801708.

The previous prime is 9991801679. The next prime is 9991801753. The reversal of 9991801709 is 9071081999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8260992100 + 1730809609 = 90890^2 + 41603^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9991801709 is a prime.

It is a super-2 number, since 2×9991801709² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9991801609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995900854 + 4995900855.

It is an arithmetic number, because the mean of its divisors is an integer number (4995900855).

Almost surely, 2^9991801709 is an apocalyptic number.

It is an amenable number.

9991801709 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991801709 is an equidigital number, since it uses as much as digits as its factorization.

9991801709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 367416, while the sum is 53.

The square root of 9991801709 is about 99959.0001400574. Note that the first 3 decimals coincide. The cubic root of 9991801709 is about 2153.8457729811.

The spelling of 9991801709 in words is "nine billion, nine hundred ninety-one million, eight hundred one thousand, seven hundred nine".