643012665 has 8 divisors (see below), whose sum is σ = 1028820288. Its totient is φ = 342940080.

The previous prime is 643012639. The next prime is 643012673. The reversal of 643012665 is 566210346.

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

It is not a de Polignac number, because 643012665 - 2¹³ = 643004473 is a prime.

It is a Curzon number.

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, 21433741 + ... + 21433770.

It is an arithmetic number, because the mean of its divisors is an integer number (128602536).

Almost surely, 2^643012665 is an apocalyptic number.

It is an amenable number.

643012665 is a deficient number, since it is larger than the sum of its proper divisors (385807623).

643012665 is a wasteful number, since it uses less digits than its factorization.

643012665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42867519.

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 643012665 is about 25357.6943944042. The cubic root of 643012665 is about 863.1239660492.

It can be divided in two parts, 64301 and 2665, that added together give a palindrome (66966).

The spelling of 643012665 in words is "six hundred forty-three million, twelve thousand, six hundred sixty-five".