16664405 has 8 divisors (see below), whose sum is σ = 20033592. Its totient is φ = 13307328.

The previous prime is 16664399. The next prime is 16664411. The reversal of 16664405 is 50446661.

16664405 is nontrivially palindromic in base 7.

It is an interprime number because it is at equal distance from previous prime (16664399) and next prime (16664411).

It can be written as a sum of positive squares in 4 ways, for example, as 1681 + 16662724 = 41^2 + 4082^2 .

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 16664405 - 2⁶ = 16664341 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 347 + ... + 5783.

It is an arithmetic number, because the mean of its divisors is an integer number (2504199).

Almost surely, 2^16664405 is an apocalyptic number.

It is an amenable number.

16664405 is a deficient number, since it is larger than the sum of its proper divisors (3369187).

16664405 is an equidigital number, since it uses as much as digits as its factorization.

16664405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6055.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 16664405 is about 4082.2058987758. The cubic root of 16664405 is about 255.4249226985.

The spelling of 16664405 in words is "sixteen million, six hundred sixty-four thousand, four hundred five".