66715977600 has 288 divisors, whose sum is σ = 238509343800. Its totient is φ = 17757204480.

The previous prime is 66715977593. The next prime is 66715977659. The reversal of 66715977600 is 677951766.

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 polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 17652511 + ... + 17656289.

Almost surely, 2^66715977600 is an apocalyptic number.

66715977600 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 66715977600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119254671900).

66715977600 is an abundant number, since it is smaller than the sum of its proper divisors (171793366200).

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

66715977600 is a wasteful number, since it uses less digits than its factorization.

66715977600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4422 (or 4402 counting only the distinct ones).

The product of its (nonzero) digits is 3333960, while the sum is 54.

The spelling of 66715977600 in words is "sixty-six billion, seven hundred fifteen million, nine hundred seventy-seven thousand, six hundred".