643433956 has 27 divisors (see below), whose sum is σ = 1238754153. Its totient is φ = 292216320.

The previous prime is 643433941. The next prime is 643433977. The reversal of 643433956 is 659334346.

The square root of 643433956 is 25366.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 508502500 + 134931456 = 22550^2 + 11616^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 557476 + ... + 558628.

Almost surely, 2^643433956 is an apocalyptic number.

643433956 is the 25366-th square number.

It is an amenable number.

643433956 is a deficient number, since it is larger than the sum of its proper divisors (595320197).

643433956 is a wasteful number, since it uses less digits than its factorization.

643433956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2332 (or 1166 counting only the distinct ones).

The product of its digits is 699840, while the sum is 43.

The cubic root of 643433956 is about 863.3124262945.

The spelling of 643433956 in words is "six hundred forty-three million, four hundred thirty-three thousand, nine hundred fifty-six".