643505746 has 8 divisors (see below), whose sum is σ = 1039509324. Its totient is φ = 297002640.

The previous prime is 643505741. The next prime is 643505747. The reversal of 643505746 is 647505346.

643505746 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 538750521 + 104755225 = 23211^2 + 10235^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 643505699 and 643505708.

It is not an unprimeable number, because it can be changed into a prime (643505741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12375085 + ... + 12375136.

Almost surely, 2^643505746 is an apocalyptic number.

643505746 is a deficient number, since it is larger than the sum of its proper divisors (396003578).

643505746 is a wasteful number, since it uses less digits than its factorization.

643505746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24750236.

The product of its (nonzero) digits is 302400, while the sum is 40.

The square root of 643505746 is about 25367.4150437131. The cubic root of 643505746 is about 863.3445326169.

The spelling of 643505746 in words is "six hundred forty-three million, five hundred five thousand, seven hundred forty-six".