644147016 has 64 divisors (see below), whose sum is σ = 1734635520. Its totient is φ = 198749760.

The previous prime is 644146999. The next prime is 644147029. The reversal of 644147016 is 610741446.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1710 + ... + 35933.

It is an arithmetic number, because the mean of its divisors is an integer number (27103680).

Almost surely, 2^644147016 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 644147016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (867317760).

644147016 is an abundant number, since it is smaller than the sum of its proper divisors (1090488504).

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

644147016 is a wasteful number, since it uses less digits than its factorization.

644147016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37706 (or 37702 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 33.

The square root of 644147016 is about 25380.0515365907. The cubic root of 644147016 is about 863.6312190732.

The spelling of 644147016 in words is "six hundred forty-four million, one hundred forty-seven thousand, sixteen".