1664028209 has 2 divisors, whose sum is σ = 1664028210. Its totient is φ = 1664028208.

The previous prime is 1664028103. The next prime is 1664028217. The reversal of 1664028209 is 9028204661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1225000000 + 439028209 = 35000^2 + 20953^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1664028209 is a prime.

It is not a weakly prime, because it can be changed into another prime (1664028229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832014104 + 832014105.

It is an arithmetic number, because the mean of its divisors is an integer number (832014105).

Almost surely, 2^1664028209 is an apocalyptic number.

It is an amenable number.

1664028209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664028209 is an equidigital number, since it uses as much as digits as its factorization.

1664028209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 1664028209 is about 40792.5018722804. The cubic root of 1664028209 is about 1185.0051235632.

The spelling of 1664028209 in words is "one billion, six hundred sixty-four million, twenty-eight thousand, two hundred nine".