664728480 has 144 divisors (see below), whose sum is σ = 2442945960. Its totient is φ = 163620864.

The previous prime is 664728469. The next prime is 664728481. The reversal of 664728480 is 84827466.

It can be written as a sum of positive squares in 4 ways, for example, as 263607696 + 401120784 = 16236^2 + 20028^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×664728480² = 883727904246220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (664728481) 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 23 ways as a sum of consecutive naturals, for example, 966 + ... + 36474.

Almost surely, 2^664728480 is an apocalyptic number.

664728480 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664728480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1221472980).

664728480 is an abundant number, since it is smaller than the sum of its proper divisors (1778217480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664728480 is a wasteful number, since it uses less digits than its factorization.

664728480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35543 (or 35532 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 45.

The square root of 664728480 is about 25782.3288319733. The cubic root of 664728480 is about 872.7330619881.

The spelling of 664728480 in words is "six hundred sixty-four million, seven hundred twenty-eight thousand, four hundred eighty".