640664640000 has 2400 divisors, whose sum is σ = 3015248011776. Its totient is φ = 131880960000.

The previous prime is 640664639999. The next prime is 640664640023. The reversal of 640664640000 is 46466046.

It is a happy number.

640664640000 is a `hidden beast` number, since 6 + 4 + 0 + 6 + 6 + 4 + 640 + 0 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (2400).

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

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 5987519947 + ... + 5987520053.

Almost surely, 2^640664640000 is an apocalyptic number.

640664640000 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 640664640000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1507624005888).

640664640000 is an abundant number, since it is smaller than the sum of its proper divisors (2374583371776).

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

640664640000 is an equidigital number, since it uses as much as digits as its factorization.

640664640000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178 (or 135 counting only the distinct ones).

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

The spelling of 640664640000 in words is "six hundred forty billion, six hundred sixty-four million, six hundred forty thousand".