643885746 has 16 divisors (see below), whose sum is σ = 1471738944. Its totient is φ = 183967344.

The previous prime is 643885687. The next prime is 643885747. The reversal of 643885746 is 647588346.

It is not an unprimeable number, because it can be changed into a prime (643885747) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7665265 + ... + 7665348.

It is an arithmetic number, because the mean of its divisors is an integer number (91983684).

Almost surely, 2^643885746 is an apocalyptic number.

643885746 is an abundant number, since it is smaller than the sum of its proper divisors (827853198).

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

643885746 is a wasteful number, since it uses less digits than its factorization.

643885746 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15330625.

The product of its digits is 3870720, while the sum is 51.

The square root of 643885746 is about 25374.9038618868. The cubic root of 643885746 is about 863.5144385676.

The spelling of 643885746 in words is "six hundred forty-three million, eight hundred eighty-five thousand, seven hundred forty-six".