1664323897 has 2 divisors, whose sum is σ = 1664323898. Its totient is φ = 1664323896.

The previous prime is 1664323879. The next prime is 1664324017. The reversal of 1664323897 is 7983234661.

Together with previous prime (1664323879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1598080576 + 66243321 = 39976^2 + 8139^2 .

It is a cyclic number.

It is not a de Polignac number, because 1664323897 - 2²⁷ = 1530106169 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1664323897.

It is not a weakly prime, because it can be changed into another prime (1664323847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832161948 + 832161949.

It is an arithmetic number, because the mean of its divisors is an integer number (832161949).

Almost surely, 2^1664323897 is an apocalyptic number.

It is an amenable number.

1664323897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664323897 is an equidigital number, since it uses as much as digits as its factorization.

1664323897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1306368, while the sum is 49.

The square root of 1664323897 is about 40796.1260048059. The cubic root of 1664323897 is about 1185.0753088804.

The spelling of 1664323897 in words is "one billion, six hundred sixty-four million, three hundred twenty-three thousand, eight hundred ninety-seven".