643746708 has 72 divisors (see below), whose sum is σ = 1793588160. Its totient is φ = 193052160.

The previous prime is 643746703. The next prime is 643746721. The reversal of 643746708 is 807647346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643746703) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30033 + ... + 46791.

Almost surely, 2^643746708 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 643746708, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (896794080).

643746708 is an abundant number, since it is smaller than the sum of its proper divisors (1149841452).

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

643746708 is a wasteful number, since it uses less digits than its factorization.

643746708 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16877 (or 16872 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 45.

The square root of 643746708 is about 25372.1640385679. The cubic root of 643746708 is about 863.4522795256.

The spelling of 643746708 in words is "six hundred forty-three million, seven hundred forty-six thousand, seven hundred eight".