1668425989 has 4 divisors (see below), whose sum is σ = 1669547980. Its totient is φ = 1667304000.

The previous prime is 1668425981. The next prime is 1668426047. The reversal of 1668425989 is 9895248661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 674285089 + 994140900 = 25967^2 + 31530^2 .

It is a cyclic number.

It is not a de Polignac number, because 1668425989 - 2³ = 1668425981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668425981) 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 in 3 ways as a sum of consecutive naturals, for example, 558762 + ... + 561739.

It is an arithmetic number, because the mean of its divisors is an integer number (417386995).

Almost surely, 2^1668425989 is an apocalyptic number.

It is an amenable number.

1668425989 is a deficient number, since it is larger than the sum of its proper divisors (1121991).

1668425989 is a wasteful number, since it uses less digits than its factorization.

1668425989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1121990.

The product of its digits is 7464960, while the sum is 58.

The square root of 1668425989 is about 40846.3705731611. The cubic root of 1668425989 is about 1186.0481362466.

The spelling of 1668425989 in words is "one billion, six hundred sixty-eight million, four hundred twenty-five thousand, nine hundred eighty-nine".