16668389 has 8 divisors (see below), whose sum is σ = 17280120. Its totient is φ = 16065216.

The previous prime is 16668361. The next prime is 16668401. The reversal of 16668389 is 98386661.

It can be written as a sum of positive squares in 4 ways, for example, as 9351364 + 7317025 = 3058^2 + 2705^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16668389 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 (16668319) 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, 1967 + ... + 6099.

It is an arithmetic number, because the mean of its divisors is an integer number (2160015).

Almost surely, 2^16668389 is an apocalyptic number.

It is an amenable number.

16668389 is a deficient number, since it is larger than the sum of its proper divisors (611731).

16668389 is a wasteful number, since it uses less digits than its factorization.

16668389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4279.

The product of its digits is 373248, while the sum is 47.

The square root of 16668389 is about 4082.6938410809. The cubic root of 16668389 is about 255.4452760966.

The spelling of 16668389 in words is "sixteen million, six hundred sixty-eight thousand, three hundred eighty-nine".