644873707296 has 1152 divisors, whose sum is σ = 2470051584000. Its totient is φ = 158018273280.

The previous prime is 644873707277. The next prime is 644873707297. The reversal of 644873707296 is 692707378446.

It is a happy number.

644873707296 is a `hidden beast` number, since 6 + 448 + 7 + 37 + 0 + 72 + 96 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (644873707297) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2379607641 + ... + 2379607911.

It is an arithmetic number, because the mean of its divisors is an integer number (2144142000).

Almost surely, 2^644873707296 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 644873707296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1235025792000).

644873707296 is an abundant number, since it is smaller than the sum of its proper divisors (1825177876704).

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

644873707296 is a wasteful number, since it uses less digits than its factorization.

644873707296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447 (or 422 counting only the distinct ones).

The product of its (nonzero) digits is 85349376, while the sum is 63.

The spelling of 644873707296 in words is "six hundred forty-four billion, eight hundred seventy-three million, seven hundred seven thousand, two hundred ninety-six".