1668683509 has 2 divisors, whose sum is σ = 1668683510. Its totient is φ = 1668683508.

The previous prime is 1668683491. The next prime is 1668683537. The reversal of 1668683509 is 9053868661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1591770609 + 76912900 = 39897^2 + 8770^2 .

It is a cyclic number.

It is not a de Polignac number, because 1668683509 - 2¹³ = 1668675317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668683309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834341754 + 834341755.

It is an arithmetic number, because the mean of its divisors is an integer number (834341755).

Almost surely, 2^1668683509 is an apocalyptic number.

It is an amenable number.

1668683509 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668683509 is an equidigital number, since it uses as much as digits as its factorization.

1668683509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1866240, while the sum is 52.

The square root of 1668683509 is about 40849.5227511901. The cubic root of 1668683509 is about 1186.1091549163.

The spelling of 1668683509 in words is "one billion, six hundred sixty-eight million, six hundred eighty-three thousand, five hundred nine".