999999999999989 has 2 divisors, whose sum is σ = 999999999999990. Its totient is φ = 999999999999988.

The previous prime is 999999999999947. The next prime is 1000000000000037. The reversal of 999999999999989 is 989999999999999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 693681921216964 + 306318078783025 = 26337842^2 + 17501945^2 .

It is a cyclic number.

It is not a de Polignac number, because 999999999999989 - 2²⁰ = 999999998951413 is a prime.

It is a super-9 number, since 9×999999999999989⁹ (a number of 136 digits) contains 999999999 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999999999999089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999999999994 + 499999999999995.

It is an arithmetic number, because the mean of its divisors is an integer number (499999999999995).

Almost surely, 2^{999999999999989} is an apocalyptic number.

It is an amenable number.

999999999999989 is a deficient number, since it is larger than the sum of its proper divisors (1).

999999999999989 is an equidigital number, since it uses as much as digits as its factorization.

999999999999989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 183014339639688, while the sum is 134.

The spelling of 999999999999989 in words is "nine hundred ninety-nine trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred eighty-nine".