1999611811 has 4 divisors (see below), whose sum is σ = 1999701400. Its totient is φ = 1999522224.

The previous prime is 1999611793. The next prime is 1999611841. The reversal of 1999611811 is 1181169991.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1999611811 - 2¹¹ = 1999609763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1999611841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18460 + ... + 65878.

It is an arithmetic number, because the mean of its divisors is an integer number (499925350).

Almost surely, 2^1999611811 is an apocalyptic number.

1999611811 is a deficient number, since it is larger than the sum of its proper divisors (89589).

1999611811 is an equidigital number, since it uses as much as digits as its factorization.

1999611811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89588.

The product of its digits is 34992, while the sum is 46.

The square root of 1999611811 is about 44717.0192544181. The cubic root of 1999611811 is about 1259.8395300384.

The spelling of 1999611811 in words is "one billion, nine hundred ninety-nine million, six hundred eleven thousand, eight hundred eleven".