1999068191 has 4 divisors (see below), whose sum is σ = 1999854384. Its totient is φ = 1998282000.

The previous prime is 1999068173. The next prime is 1999068193. The reversal of 1999068191 is 1918609991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1999068191 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999068193) 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 in 3 ways as a sum of consecutive naturals, for example, 389270 + ... + 394371.

It is an arithmetic number, because the mean of its divisors is an integer number (499963596).

Almost surely, 2^1999068191 is an apocalyptic number.

1999068191 is a deficient number, since it is larger than the sum of its proper divisors (786193).

1999068191 is an equidigital number, since it uses as much as digits as its factorization.

1999068191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 786192.

The product of its (nonzero) digits is 314928, while the sum is 53.

The square root of 1999068191 is about 44710.9403949414. The cubic root of 1999068191 is about 1259.7253518706.

The spelling of 1999068191 in words is "one billion, nine hundred ninety-nine million, sixty-eight thousand, one hundred ninety-one".