643354665 has 8 divisors (see below), whose sum is σ = 1029367488. Its totient is φ = 343122480.

The previous prime is 643354639. The next prime is 643354711. The reversal of 643354665 is 566453346.

It is a happy number.

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

It is not a de Polignac number, because 643354665 - 2⁵ = 643354633 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21445141 + ... + 21445170.

It is an arithmetic number, because the mean of its divisors is an integer number (128670936).

Almost surely, 2^643354665 is an apocalyptic number.

It is an amenable number.

643354665 is a deficient number, since it is larger than the sum of its proper divisors (386012823).

643354665 is a wasteful number, since it uses less digits than its factorization.

643354665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42890319.

The product of its digits is 777600, while the sum is 42.

The square root of 643354665 is about 25364.4370132672. The cubic root of 643354665 is about 863.2769625576.

The spelling of 643354665 in words is "six hundred forty-three million, three hundred fifty-four thousand, six hundred sixty-five".