999111999001 has 2 divisors, whose sum is σ = 999111999002. Its totient is φ = 999111999000.

The previous prime is 999111998953. The next prime is 999111999031. The reversal of 999111999001 is 100999111999.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 922838816025 + 76273182976 = 960645^2 + 276176^2 .

It is a cyclic number.

It is not a de Polignac number, because 999111999001 - 2²⁷ = 998977781273 is a prime.

It is not a weakly prime, because it can be changed into another prime (999111999031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499555999500 + 499555999501.

It is an arithmetic number, because the mean of its divisors is an integer number (499555999501).

Almost surely, 2^999111999001 is an apocalyptic number.

It is an amenable number.

999111999001 is a deficient number, since it is larger than the sum of its proper divisors (1).

999111999001 is an equidigital number, since it uses as much as digits as its factorization.

999111999001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 531441, while the sum is 58.

The spelling of 999111999001 in words is "nine hundred ninety-nine billion, one hundred eleven million, nine hundred ninety-nine thousand, one".