643969346 has 4 divisors (see below), whose sum is σ = 965954022. Its totient is φ = 321984672.

The previous prime is 643969343. The next prime is 643969363.

It is a happy number.

643969346 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 547045321 + 96924025 = 23389^2 + 9845^2 .

It is a junction number, because it is equal to n+sod(n) for n = 643969294 and 643969303.

It is not an unprimeable number, because it can be changed into a prime (643969343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160992335 + ... + 160992338.

Almost surely, 2^643969346 is an apocalyptic number.

643969346 is a deficient number, since it is larger than the sum of its proper divisors (321984676).

643969346 is a wasteful number, since it uses less digits than its factorization.

643969346 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321984675.

The product of its digits is 2519424, while the sum is 50.

The square root of 643969346 is about 25376.5511053019. The cubic root of 643969346 is about 863.5518089051.

The spelling of 643969346 in words is "six hundred forty-three million, nine hundred sixty-nine thousand, three hundred forty-six".