644045540444 has 12 divisors (see below), whose sum is σ = 1129234727544. Its totient is φ = 321407046864.

The previous prime is 644045540407. The next prime is 644045540513. The reversal of 644045540444 is 444045540446.

It is a junction number, because it is equal to n+sod(n) for n = 644045540395 and 644045540404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 153928487 + ... + 153932670.

It is an arithmetic number, because the mean of its divisors is an integer number (94102893962).

Almost surely, 2^644045540444 is an apocalyptic number.

It is an amenable number.

644045540444 is a deficient number, since it is larger than the sum of its proper divisors (485189187100).

644045540444 is a wasteful number, since it uses less digits than its factorization.

644045540444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307861684 (or 307861682 counting only the distinct ones).

The product of its (nonzero) digits is 2457600, while the sum is 44.

The spelling of 644045540444 in words is "six hundred forty-four billion, forty-five million, five hundred forty thousand, four hundred forty-four".