664768205 has 4 divisors (see below), whose sum is σ = 797721852. Its totient is φ = 531814560.

The previous prime is 664768199. The next prime is 664768207. The reversal of 664768205 is 502867466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 502867466 = 2 ⋅251433733.

It can be written as a sum of positive squares in 2 ways, for example, as 322777156 + 341991049 = 17966^2 + 18493^2 .

It is not a de Polignac number, because 664768205 - 2¹² = 664764109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664768207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66476816 + ... + 66476825.

It is an arithmetic number, because the mean of its divisors is an integer number (199430463).

Almost surely, 2^664768205 is an apocalyptic number.

It is an amenable number.

664768205 is a deficient number, since it is larger than the sum of its proper divisors (132953647).

664768205 is a wasteful number, since it uses less digits than its factorization.

664768205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132953646.

The product of its (nonzero) digits is 483840, while the sum is 44.

The square root of 664768205 is about 25783.0992124686. The cubic root of 664768205 is about 872.7504468459.

The spelling of 664768205 in words is "six hundred sixty-four million, seven hundred sixty-eight thousand, two hundred five".