1691911811 has 2 divisors, whose sum is σ = 1691911812. Its totient is φ = 1691911810.

The previous prime is 1691911787. The next prime is 1691911817. The reversal of 1691911811 is 1181191961.

It is a strong prime.

It is an emirp because it is prime and its reverse (1181191961) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1181161691 and 1961611811.

It is a cyclic number.

It is not a de Polignac number, because 1691911811 - 2¹⁴ = 1691895427 is a prime.

It is not a weakly prime, because it can be changed into another prime (1691911817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 845955905 + 845955906.

It is an arithmetic number, because the mean of its divisors is an integer number (845955906).

Almost surely, 2^1691911811 is an apocalyptic number.

1691911811 is a deficient number, since it is larger than the sum of its proper divisors (1).

1691911811 is an equidigital number, since it uses as much as digits as its factorization.

1691911811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 38.

The square root of 1691911811 is about 41132.8556144598. The cubic root of 1691911811 is about 1191.5874140283.

The spelling of 1691911811 in words is "one billion, six hundred ninety-one million, nine hundred eleven thousand, eight hundred eleven".