16664421 has 8 divisors (see below), whose sum is σ = 22282560. Its totient is φ = 11077952.

The previous prime is 16664411. The next prime is 16664447. The reversal of 16664421 is 12446661.

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 16664421 - 2¹⁰ = 16663397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16664411) 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, 6660 + ... + 8813.

It is an arithmetic number, because the mean of its divisors is an integer number (2785320).

Almost surely, 2^16664421 is an apocalyptic number.

It is an amenable number.

16664421 is a deficient number, since it is larger than the sum of its proper divisors (5618139).

16664421 is a wasteful number, since it uses less digits than its factorization.

16664421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15835.

The product of its digits is 6912, while the sum is 30.

The square root of 16664421 is about 4082.2078585001. The cubic root of 16664421 is about 255.4250044456.

The spelling of 16664421 in words is "sixteen million, six hundred sixty-four thousand, four hundred twenty-one".