664561653120 has 512 divisors, whose sum is σ = 2423275200000. Its totient is φ = 171998650368.

The previous prime is 664561653103. The next prime is 664561653131. The reversal of 664561653120 is 21356165466.

664561653120 is a `hidden beast` number, since 6 + 6 + 4 + 5 + 616 + 5 + 3 + 1 + 20 = 666.

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

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 319039599 + ... + 319041681.

It is an arithmetic number, because the mean of its divisors is an integer number (4732959375).

Almost surely, 2^664561653120 is an apocalyptic number.

664561653120 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 664561653120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1211637600000).

664561653120 is an abundant number, since it is smaller than the sum of its proper divisors (1758713546880).

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

664561653120 is a wasteful number, since it uses less digits than its factorization.

664561653120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2647 (or 2629 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 664561653120 in words is "six hundred sixty-four billion, five hundred sixty-one million, six hundred fifty-three thousand, one hundred twenty".