664215605 has 4 divisors (see below), whose sum is σ = 797058732. Its totient is φ = 531372480.

The previous prime is 664215581. The next prime is 664215611. The reversal of 664215605 is 506512466.

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

It can be written as a sum of positive squares in 2 ways, for example, as 378808369 + 285407236 = 19463^2 + 16894^2 .

It is not a de Polignac number, because 664215605 - 2²⁸ = 395780149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66421556 + ... + 66421565.

It is an arithmetic number, because the mean of its divisors is an integer number (199264683).

Almost surely, 2^664215605 is an apocalyptic number.

It is an amenable number.

664215605 is a deficient number, since it is larger than the sum of its proper divisors (132843127).

664215605 is a wasteful number, since it uses less digits than its factorization.

664215605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132843126.

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 664215605 is about 25772.3806622516. The cubic root of 664215605 is about 872.5085502018.

The spelling of 664215605 in words is "six hundred sixty-four million, two hundred fifteen thousand, six hundred five".