66484779840 has 168 divisors, whose sum is σ = 229496541768. Its totient is φ = 17665966080.

The previous prime is 66484779821. The next prime is 66484779859. The reversal of 66484779840 is 4897748466.

66484779840 is a `hidden beast` number, since 6 + 6 + 484 + 7 + 79 + 84 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (66484779821) and next prime (66484779859).

It can be written as a sum of positive squares in 4 ways, for example, as 3920763456 + 62564016384 = 62616^2 + 250128^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 768204 + ... + 850356.

Almost surely, 2^66484779840 is an apocalyptic number.

66484779840 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 66484779840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114748270884).

66484779840 is an abundant number, since it is smaller than the sum of its proper divisors (163011761928).

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

66484779840 is a wasteful number, since it uses less digits than its factorization.

66484779840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82457 (or 82444 counting only the distinct ones).

The product of its (nonzero) digits is 65028096, while the sum is 63.

The spelling of 66484779840 in words is "sixty-six billion, four hundred eighty-four million, seven hundred seventy-nine thousand, eight hundred forty".