643413665 has 8 divisors (see below), whose sum is σ = 784754088. Its totient is φ = 506292480.

The previous prime is 643413653. The next prime is 643413689. The reversal of 643413665 is 566314346.

643413665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 9935104 + 633478561 = 3152^2 + 25169^2 .

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

It is not a de Polignac number, because 643413665 - 2¹⁶ = 643348129 is a prime.

It is a super-2 number, since 2×643413665² = 827962288617464450, which contains 22 as substring.

It is a Duffinian 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, 1054472 + ... + 1055081.

It is an arithmetic number, because the mean of its divisors is an integer number (98094261).

Almost surely, 2^643413665 is an apocalyptic number.

It is an amenable number.

643413665 is a deficient number, since it is larger than the sum of its proper divisors (141340423).

643413665 is a wasteful number, since it uses less digits than its factorization.

643413665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2109619.

The product of its digits is 155520, while the sum is 38.

The square root of 643413665 is about 25365.6000323272. The cubic root of 643413665 is about 863.3033512079.

The spelling of 643413665 in words is "six hundred forty-three million, four hundred thirteen thousand, six hundred sixty-five".