1664680091 has 2 divisors, whose sum is σ = 1664680092. Its totient is φ = 1664680090.

The previous prime is 1664680037. The next prime is 1664680097. The reversal of 1664680091 is 1900864661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1664680091 - 2³⁰ = 590938267 is a prime.

It is not a weakly prime, because it can be changed into another prime (1664680097) 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, 832340045 + 832340046.

It is an arithmetic number, because the mean of its divisors is an integer number (832340046).

Almost surely, 2^1664680091 is an apocalyptic number.

1664680091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664680091 is an equidigital number, since it uses as much as digits as its factorization.

1664680091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 1664680091 is about 40800.4913083164. The cubic root of 1664680091 is about 1185.1598450306.

The spelling of 1664680091 in words is "one billion, six hundred sixty-four million, six hundred eighty thousand, ninety-one".