1668497989 has 8 divisors (see below), whose sum is σ = 1684809720. Its totient is φ = 1652204736.

The previous prime is 1668497983. The next prime is 1668498049. The reversal of 1668497989 is 9897948661.

It can be written as a sum of positive squares in 4 ways, for example, as 1054300900 + 614197089 = 32470^2 + 24783^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1668497989 - 2²⁷ = 1534280261 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 (1668497983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 237759 + ... + 244675.

It is an arithmetic number, because the mean of its divisors is an integer number (210601215).

Almost surely, 2^1668497989 is an apocalyptic number.

It is an amenable number.

1668497989 is a deficient number, since it is larger than the sum of its proper divisors (16311731).

1668497989 is a wasteful number, since it uses less digits than its factorization.

1668497989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9239.

The product of its digits is 47029248, while the sum is 67.

The square root of 1668497989 is about 40847.2519149085. The cubic root of 1668497989 is about 1186.0651970848.

The spelling of 1668497989 in words is "one billion, six hundred sixty-eight million, four hundred ninety-seven thousand, nine hundred eighty-nine".