643666346 has 8 divisors (see below), whose sum is σ = 968585124. Its totient is φ = 320804640.

The previous prime is 643666343. The next prime is 643666351.

It is a happy number.

643666346 is nontrivially palindromic in base 10.

643666346 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 642876025 + 790321 = 25355^2 + 889^2 .

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 = 643666297 and 643666306.

It is not an unprimeable number, because it can be changed into a prime (643666343) 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, 513485 + ... + 514736.

Almost surely, 2^643666346 is an apocalyptic number.

643666346 is a deficient number, since it is larger than the sum of its proper divisors (324918778).

643666346 is a wasteful number, since it uses less digits than its factorization.

643666346 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1028536.

The product of its digits is 1119744, while the sum is 44.

The square root of 643666346 is about 25370.5803244624. The cubic root of 643666346 is about 863.4163483958.

The spelling of 643666346 in words is "six hundred forty-three million, six hundred sixty-six thousand, three hundred forty-six".