66715655616 has 224 divisors, whose sum is σ = 201255782400. Its totient is φ = 21664419840.

The previous prime is 66715655561. The next prime is 66715655731. The reversal of 66715655616 is 61655651766.

66715655616 is a `hidden beast` number, since 6 + 6 + 7 + 15 + 6 + 5 + 5 + 616 = 666.

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 31 ways as a sum of consecutive naturals, for example, 11517681 + ... + 11523471.

Almost surely, 2^66715655616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66715655616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100627891200).

66715655616 is an abundant number, since it is smaller than the sum of its proper divisors (134540126784).

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

66715655616 is a wasteful number, since it uses less digits than its factorization.

66715655616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5984 (or 5968 counting only the distinct ones).

The product of its digits is 6804000, while the sum is 54.

The spelling of 66715655616 in words is "sixty-six billion, seven hundred fifteen million, six hundred fifty-five thousand, six hundred sixteen".