66816983520 has 288 divisors, whose sum is σ = 271917015552. Its totient is φ = 14608382976.

The previous prime is 66816983501. The next prime is 66816983533. The reversal of 66816983520 is 2538961866.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 87739 + ... + 375941.

It is an arithmetic number, because the mean of its divisors is an integer number (944156304).

Almost surely, 2^66816983520 is an apocalyptic number.

66816983520 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 66816983520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135958507776).

66816983520 is an abundant number, since it is smaller than the sum of its proper divisors (205100032032).

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

66816983520 is a wasteful number, since it uses less digits than its factorization.

66816983520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288254 (or 288243 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 54.

It can be divided in two parts, 668169 and 83520, that added together give a square (751689 = 867²).

The spelling of 66816983520 in words is "sixty-six billion, eight hundred sixteen million, nine hundred eighty-three thousand, five hundred twenty".