989818909 has 2 divisors, whose sum is σ = 989818910. Its totient is φ = 989818908.

The previous prime is 989818891. The next prime is 989818957. The reversal of 989818909 is 909818989.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 958212025 + 31606884 = 30955^2 + 5622^2 .

It is a cyclic number.

It is not a de Polignac number, because 989818909 - 2¹⁵ = 989786141 is a prime.

It is a super-2 number, since 2×989818909² = 1959482945227900562, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989815909) 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, 494909454 + 494909455.

It is an arithmetic number, because the mean of its divisors is an integer number (494909455).

Almost surely, 2^989818909 is an apocalyptic number.

It is an amenable number.

989818909 is a deficient number, since it is larger than the sum of its proper divisors (1).

989818909 is an equidigital number, since it uses as much as digits as its factorization.

989818909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3359232, while the sum is 61.

The square root of 989818909 is about 31461.3875885982. The cubic root of 989818909 is about 996.5947202322.

The spelling of 989818909 in words is "nine hundred eighty-nine million, eight hundred eighteen thousand, nine hundred nine".