1644444263 has 12 divisors (see below), whose sum is σ = 2086827912. Its totient is φ = 1281384720.

The previous prime is 1644444247. The next prime is 1644444287. The reversal of 1644444263 is 3624444461.

It is not a de Polignac number, because 1644444263 - 2⁴ = 1644444247 is a prime.

It is a super-2 number, since 2×1644444263² = 5408393868227226338, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644444203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1524920 + ... + 1525997.

It is an arithmetic number, because the mean of its divisors is an integer number (173902326).

Almost surely, 2^1644444263 is an apocalyptic number.

1644444263 is a deficient number, since it is larger than the sum of its proper divisors (442383649).

1644444263 is a wasteful number, since it uses less digits than its factorization.

1644444263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3050942 (or 3050935 counting only the distinct ones).

The product of its digits is 221184, while the sum is 38.

The square root of 1644444263 is about 40551.7479647919. The cubic root of 1644444263 is about 1180.3379916111.

The spelling of 1644444263 in words is "one billion, six hundred forty-four million, four hundred forty-four thousand, two hundred sixty-three".