660464640 has 264 divisors, whose sum is σ = 2498453568. Its totient is φ = 159989760.

The previous prime is 660464593. The next prime is 660464663. The reversal of 660464640 is 46464066.

It is a happy number.

660464640 is a `hidden beast` number, since 6 + 6 + 0 + 4 + 6 + 4 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (264).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 660464595 and 660464604.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 506229 + ... + 507531.

Almost surely, 2^660464640 is an apocalyptic number.

660464640 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 660464640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1249226784).

660464640 is an abundant number, since it is smaller than the sum of its proper divisors (1837988928).

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

660464640 is a wasteful number, since it uses less digits than its factorization.

660464640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1345 (or 1324 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The square root of 660464640 is about 25699.5066100499. The cubic root of 660464640 is about 870.8630357814.

The spelling of 660464640 in words is "six hundred sixty million, four hundred sixty-four thousand, six hundred forty".