644449772276 has 24 divisors (see below), whose sum is σ = 1154359999296. Its totient is φ = 314717459840.

The previous prime is 644449772251. The next prime is 644449772297. The reversal of 644449772276 is 672277944446.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 10573301 + ... + 10634076.

It is an arithmetic number, because the mean of its divisors is an integer number (48098333304).

Almost surely, 2^644449772276 is an apocalyptic number.

It is an amenable number.

644449772276 is a deficient number, since it is larger than the sum of its proper divisors (509910227020).

644449772276 is a wasteful number, since it uses less digits than its factorization.

644449772276 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21207559 (or 21207557 counting only the distinct ones).

The product of its digits is 113799168, while the sum is 62.

The spelling of 644449772276 in words is "six hundred forty-four billion, four hundred forty-nine million, seven hundred seventy-two thousand, two hundred seventy-six".