9990561709 has 2 divisors, whose sum is σ = 9990561710. Its totient is φ = 9990561708.

The previous prime is 9990561701. The next prime is 9990561829. The reversal of 9990561709 is 9071650999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8290648809 + 1699912900 = 91053^2 + 41230^2 .

It is a cyclic number.

It is not a de Polignac number, because 9990561709 - 2³ = 9990561701 is a prime.

It is a super-2 number, since 2×9990561709² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 9990561709.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9990561701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995280854 + 4995280855.

It is an arithmetic number, because the mean of its divisors is an integer number (4995280855).

Almost surely, 2^9990561709 is an apocalyptic number.

It is an amenable number.

9990561709 is a deficient number, since it is larger than the sum of its proper divisors (1).

9990561709 is an equidigital number, since it uses as much as digits as its factorization.

9990561709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1377810, while the sum is 55.

The square root of 9990561709 is about 99952.7974045749. The cubic root of 9990561709 is about 2153.7566706241.

The spelling of 9990561709 in words is "nine billion, nine hundred ninety million, five hundred sixty-one thousand, seven hundred nine".