664401205347840 has 1280 divisors, whose sum is σ = 2435244134400000. Its totient is φ = 173786992017408.

The previous prime is 664401205347833. The next prime is 664401205347857. The reversal of 664401205347840 is 48743502104466.

664401205347840 is a `hidden beast` number, since 6 + 6 + 4 + 4 + 0 + 1 + 20 + 534 + 7 + 84 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1280).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 63282326911 + ... + 63282337409.

It is an arithmetic number, because the mean of its divisors is an integer number (1902534480000).

Almost surely, 2^{664401205347840} is an apocalyptic number.

664401205347840 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 664401205347840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1217622067200000).

664401205347840 is an abundant number, since it is smaller than the sum of its proper divisors (1770842929052160).

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

664401205347840 is an equidigital number, since it uses as much as digits as its factorization.

664401205347840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10759 (or 10725 counting only the distinct ones).

The product of its (nonzero) digits is 15482880, while the sum is 54.

The spelling of 664401205347840 in words is "six hundred sixty-four trillion, four hundred one billion, two hundred five million, three hundred forty-seven thousand, eight hundred forty".