1999119991 has 8 divisors (see below), whose sum is σ = 2181207168. Its totient is φ = 1817091000.

The previous prime is 1999119973. The next prime is 1999120007.

It is a happy number.

1999119991 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1999119991 - 2¹³ = 1999111799 is a prime.

It is a super-3 number, since 3×1999119991³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999110991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90006 + ... + 109996.

It is an arithmetic number, because the mean of its divisors is an integer number (272650896).

Almost surely, 2^1999119991 is an apocalyptic number.

1999119991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1999119991 is a deficient number, since it is larger than the sum of its proper divisors (182087177).

1999119991 is a wasteful number, since it uses less digits than its factorization.

1999119991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29093.

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

The square root of 1999119991 is about 44711.5196677545. The cubic root of 1999119991 is about 1259.7362324749.

It can be divided in two parts, 199911 and 9991, that added together give a palindrome (209902).

The spelling of 1999119991 in words is "one billion, nine hundred ninety-nine million, one hundred nineteen thousand, nine hundred ninety-one".