646438016 has 64 divisors (see below), whose sum is σ = 1485528000. Its totient is φ = 274461696.

The previous prime is 646437983. The next prime is 646438019. The reversal of 646438016 is 610834646.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (646438019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 94355 + ... + 100973.

It is an arithmetic number, because the mean of its divisors is an integer number (23211375).

Almost surely, 2^646438016 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 646438016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (742764000).

646438016 is an abundant number, since it is smaller than the sum of its proper divisors (839089984).

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

646438016 is a wasteful number, since it uses less digits than its factorization.

646438016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6749 (or 6737 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 38.

The square root of 646438016 is about 25425.1453486504. The cubic root of 646438016 is about 864.6538831539.

The spelling of 646438016 in words is "six hundred forty-six million, four hundred thirty-eight thousand, sixteen".