1668416989 has 2 divisors, whose sum is σ = 1668416990. Its totient is φ = 1668416988.

The previous prime is 1668416983. The next prime is 1668417011. The reversal of 1668416989 is 9896148661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1040062500 + 628354489 = 32250^2 + 25067^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668416989 is a prime.

It is a super-2 number, since 2×1668416989² = 5567230498367652242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668416983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834208494 + 834208495.

It is an arithmetic number, because the mean of its divisors is an integer number (834208495).

Almost surely, 2^1668416989 is an apocalyptic number.

It is an amenable number.

1668416989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668416989 is an equidigital number, since it uses as much as digits as its factorization.

1668416989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4478976, while the sum is 58.

The square root of 1668416989 is about 40846.2604041055. The cubic root of 1668416989 is about 1186.0460036073.

The spelling of 1668416989 in words is "one billion, six hundred sixty-eight million, four hundred sixteen thousand, nine hundred eighty-nine".