16644661 has 4 divisors (see below), whose sum is σ = 18157824. Its totient is φ = 15131500.

The previous prime is 16644629. The next prime is 16644671.

16644661 is nontrivially palindromic in base 10.

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.

It is a cyclic number.

It is not a de Polignac number, because 16644661 - 2⁵ = 16644629 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 (16644671) 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, 756565 + ... + 756586.

It is an arithmetic number, because the mean of its divisors is an integer number (4539456).

Almost surely, 2^16644661 is an apocalyptic number.

16644661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16644661 is a deficient number, since it is larger than the sum of its proper divisors (1513163).

16644661 is a wasteful number, since it uses less digits than its factorization.

16644661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1513162.

The product of its digits is 20736, while the sum is 34.

The square root of 16644661 is about 4079.7868816888. The cubic root of 16644661 is about 255.3240069507.

The spelling of 16644661 in words is "sixteen million, six hundred forty-four thousand, six hundred sixty-one".