664040643 has 16 divisors (see below), whose sum is σ = 1012859136. Its totient is φ = 379081440.

The previous prime is 664040623. The next prime is 664040687. The reversal of 664040643 is 346040466.

664040643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 664040643 - 2²⁰ = 662992067 is a prime.

It is not an unprimeable number, because it can be changed into a prime (664040623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7380 + ... + 37182.

It is an arithmetic number, because the mean of its divisors is an integer number (63303696).

Almost surely, 2^664040643 is an apocalyptic number.

664040643 is a deficient number, since it is larger than the sum of its proper divisors (348818493).

664040643 is a wasteful number, since it uses less digits than its factorization.

664040643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30874.

The product of its (nonzero) digits is 41472, while the sum is 33.

The square root of 664040643 is about 25768.9860685282. The cubic root of 664040643 is about 872.4319338915.

The spelling of 664040643 in words is "six hundred sixty-four million, forty thousand, six hundred forty-three".