1665164191 has 2 divisors, whose sum is σ = 1665164192. Its totient is φ = 1665164190.

The previous prime is 1665164173. The next prime is 1665164197. The reversal of 1665164191 is 1914615661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1665164191 - 2⁵ = 1665164159 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665164197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832582095 + 832582096.

It is an arithmetic number, because the mean of its divisors is an integer number (832582096).

Almost surely, 2^1665164191 is an apocalyptic number.

1665164191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665164191 is an equidigital number, since it uses as much as digits as its factorization.

1665164191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 40.

The square root of 1665164191 is about 40806.4234036751. The cubic root of 1665164191 is about 1185.2747180078.

The spelling of 1665164191 in words is "one billion, six hundred sixty-five million, one hundred sixty-four thousand, one hundred ninety-one".