643665011 has 8 divisors (see below), whose sum is σ = 706240944. Its totient is φ = 581765920.

The previous prime is 643664993. The next prime is 643665041. The reversal of 643665011 is 110566346.

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

It is a cyclic number.

It is not a de Polignac number, because 643665011 - 2¹⁰ = 643663987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643665041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 167216 + ... + 171021.

It is an arithmetic number, because the mean of its divisors is an integer number (88280118).

Almost surely, 2^643665011 is an apocalyptic number.

643665011 is a deficient number, since it is larger than the sum of its proper divisors (62575933).

643665011 is a wasteful number, since it uses less digits than its factorization.

643665011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338421.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 643665011 is about 25370.5540144475. The cubic root of 643665011 is about 863.4157514707.

The spelling of 643665011 in words is "six hundred forty-three million, six hundred sixty-five thousand, eleven".