16644001 has 4 divisors (see below), whose sum is σ = 18157104. Its totient is φ = 15130900.

The previous prime is 16643989. The next prime is 16644011. The reversal of 16644001 is 10044661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10044661 = 11 ⋅913151.

It is a cyclic number.

It is not a de Polignac number, because 16644001 - 2¹⁵ = 16611233 is a prime.

It is a Smith number, since the sum of its digits (22) 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 not an unprimeable number, because it can be changed into a prime (16644011) by changing a digit.

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, 756535 + ... + 756556.

It is an arithmetic number, because the mean of its divisors is an integer number (4539276).

Almost surely, 2^16644001 is an apocalyptic number.

16644001 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

16644001 is the 1825-th centered decagonal number.

It is an amenable number.

16644001 is a deficient number, since it is larger than the sum of its proper divisors (1513103).

16644001 is a wasteful number, since it uses less digits than its factorization.

16644001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1513102.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 16644001 is about 4079.7059943089. The cubic root of 16644001 is about 255.3206321734.

Adding to 16644001 its reverse (10044661), we get a palindrome (26688662).

It can be divided in two parts, 1664 and 4001, that added together give a palindrome (5665).

The spelling of 16644001 in words is "sixteen million, six hundred forty-four thousand, one".