66344559840 has 864 divisors, whose sum is σ = 265893788160. Its totient is φ = 15585343488.

The previous prime is 66344559833. The next prime is 66344559871. The reversal of 66344559840 is 4895544366.

66344559840 is a `hidden beast` number, since 6 + 6 + 3 + 4 + 4 + 5 + 598 + 40 = 666.

66344559840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (864).

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 143 ways as a sum of consecutive naturals, for example, 151126341 + ... + 151126779.

It is an arithmetic number, because the mean of its divisors is an integer number (307747440).

Almost surely, 2^66344559840 is an apocalyptic number.

66344559840 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 66344559840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132946894080).

66344559840 is an abundant number, since it is smaller than the sum of its proper divisors (199549228320).

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

66344559840 is a wasteful number, since it uses less digits than its factorization.

66344559840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518 (or 485 counting only the distinct ones).

The product of its (nonzero) digits is 12441600, while the sum is 54.

The spelling of 66344559840 in words is "sixty-six billion, three hundred forty-four million, five hundred fifty-nine thousand, eight hundred forty".