66019665600 has 840 divisors, whose sum is σ = 282121892448. Its totient is φ = 14830387200.

The previous prime is 66019665583. The next prime is 66019665601. The reversal of 66019665600 is 656691066.

It is a tau number, because it is divible by the number of its divisors (840).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (66019665601) by changing a digit.

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 119 ways as a sum of consecutive naturals, for example, 55338604 + ... + 55339796.

Almost surely, 2^66019665600 is an apocalyptic number.

66019665600 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 66019665600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141060946224).

66019665600 is an abundant number, since it is smaller than the sum of its proper divisors (216102226848).

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

66019665600 is a wasteful number, since it uses less digits than its factorization.

66019665600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1295 (or 1271 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 45.

The spelling of 66019665600 in words is "sixty-six billion, nineteen million, six hundred sixty-five thousand, six hundred".