644342555632 has 10 divisors (see below), whose sum is σ = 1248413701568. Its totient is φ = 322171277808.

The previous prime is 644342555617. The next prime is 644342555657. The reversal of 644342555632 is 236555243446.

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 as a sum of consecutive naturals, namely, 20135704848 + ... + 20135704879.

Almost surely, 2^644342555632 is an apocalyptic number.

It is an amenable number.

644342555632 is a deficient number, since it is larger than the sum of its proper divisors (604071145936).

644342555632 is a wasteful number, since it uses less digits than its factorization.

644342555632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40271409735 (or 40271409729 counting only the distinct ones).

The product of its digits is 10368000, while the sum is 49.

The spelling of 644342555632 in words is "six hundred forty-four billion, three hundred forty-two million, five hundred fifty-five thousand, six hundred thirty-two".