16644505 has 4 divisors (see below), whose sum is σ = 19973412. Its totient is φ = 13315600.

The previous prime is 16644469. The next prime is 16644527. The reversal of 16644505 is 50544661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50544661 = 61 ⋅828601.

It can be written as a sum of positive squares in 2 ways, for example, as 1990921 + 14653584 = 1411^2 + 3828^2 .

It is not a de Polignac number, because 16644505 - 2²¹ = 14547353 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1664446 + ... + 1664455.

It is an arithmetic number, because the mean of its divisors is an integer number (4993353).

Almost surely, 2^16644505 is an apocalyptic number.

It is an amenable number.

16644505 is a deficient number, since it is larger than the sum of its proper divisors (3328907).

16644505 is an equidigital number, since it uses as much as digits as its factorization.

16644505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3328906.

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 16644505 is about 4079.7677629983. The cubic root of 16644505 is about 255.3232092841.

The spelling of 16644505 in words is "sixteen million, six hundred forty-four thousand, five hundred five".