643350666 has 32 divisors (see below), whose sum is σ = 1471891968. Its totient is φ = 183642480.

The previous prime is 643350647. The next prime is 643350677. The reversal of 643350666 is 666053346.

It is a happy number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 42261 + ... + 55431.

It is an arithmetic number, because the mean of its divisors is an integer number (45996624).

Almost surely, 2^643350666 is an apocalyptic number.

643350666 is an abundant number, since it is smaller than the sum of its proper divisors (828541302).

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

643350666 is a wasteful number, since it uses less digits than its factorization.

643350666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14346.

The product of its (nonzero) digits is 233280, while the sum is 39.

The square root of 643350666 is about 25364.3581822998. The cubic root of 643350666 is about 863.2751738854.

The spelling of 643350666 in words is "six hundred forty-three million, three hundred fifty thousand, six hundred sixty-six".