It is a semiprime because it is the product of two primes.
It is a congruent number.
It is an unprimeable number.
Almost surely, 2664728478 is an apocalyptic number.
664728478 is a wasteful number, since it uses less digits than its factorization.
664728478 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 332364241.
The square root of 664728478 is about 25782.3287931870. The cubic root of 664728478 is about 872.7330611128.
The spelling of 664728478 in words is "six hundred sixty-four million, seven hundred twenty-eight thousand, four hundred seventy-eight".