664563243 has 4 divisors (see below), whose sum is σ = 886084328. Its totient is φ = 443042160.

The previous prime is 664563239. The next prime is 664563257. The reversal of 664563243 is 342365466.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 664563243 - 2² = 664563239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664563203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110760538 + ... + 110760543.

It is an arithmetic number, because the mean of its divisors is an integer number (221521082).

Almost surely, 2^664563243 is an apocalyptic number.

664563243 is a deficient number, since it is larger than the sum of its proper divisors (221521085).

664563243 is a wasteful number, since it uses less digits than its factorization.

664563243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221521084.

The product of its digits is 311040, while the sum is 39.

The square root of 664563243 is about 25779.1241705377. The cubic root of 664563243 is about 872.6607418615.

The spelling of 664563243 in words is "six hundred sixty-four million, five hundred sixty-three thousand, two hundred forty-three".