1999111111 has 2 divisors, whose sum is σ = 1999111112. Its totient is φ = 1999111110.

The previous prime is 1999111109. The next prime is 1999111123. The reversal of 1999111111 is 1111119991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1999111111 - 2¹ = 1999111109 is a prime.

Together with 1999111109, it forms a pair of twin primes.

1999111111 is a modest number, since divided by 111111 gives 1999 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999117111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999555555 + 999555556.

It is an arithmetic number, because the mean of its divisors is an integer number (999555556).

Almost surely, 2^1999111111 is an apocalyptic number.

1999111111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999111111 is an equidigital number, since it uses as much as digits as its factorization.

1999111111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 729, while the sum is 34.

The square root of 1999111111 is about 44711.4203643767. The cubic root of 1999111111 is about 1259.7343672418.

The spelling of 1999111111 in words is "one billion, nine hundred ninety-nine million, one hundred eleven thousand, one hundred eleven".