644732776752 has 160 divisors (see below), whose sum is σ = 1775232806400. Its totient is φ = 200929726464.

The previous prime is 644732776673. The next prime is 644732776783. The reversal of 644732776752 is 257677237446.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 199667874 + ... + 199671102.

It is an arithmetic number, because the mean of its divisors is an integer number (11095205040).

Almost surely, 2^644732776752 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644732776752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (887616403200).

644732776752 is an abundant number, since it is smaller than the sum of its proper divisors (1130500029648).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644732776752 is a wasteful number, since it uses less digits than its factorization.

644732776752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4803 (or 4797 counting only the distinct ones).

The product of its digits is 82978560, while the sum is 60.

The spelling of 644732776752 in words is "six hundred forty-four billion, seven hundred thirty-two million, seven hundred seventy-six thousand, seven hundred fifty-two".