16644444661 has 16 divisors (see below), whose sum is σ = 18896984064. Its totient is φ = 14544566784.

The previous prime is 16644444659. The next prime is 16644444679.

It is a happy number.

16644444661 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 16644444661 - 2¹ = 16644444659 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 (16644444361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 257941 + ... + 315946.

It is an arithmetic number, because the mean of its divisors is an integer number (1181061504).

Almost surely, 2^16644444661 is an apocalyptic number.

It is an amenable number.

16644444661 is a deficient number, since it is larger than the sum of its proper divisors (2252539403).

16644444661 is a wasteful number, since it uses less digits than its factorization.

16644444661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574020.

The product of its digits is 1327104, while the sum is 46.

The spelling of 16644444661 in words is "sixteen billion, six hundred forty-four million, four hundred forty-four thousand, six hundred sixty-one".