66615587776 has 56 divisors (see below), whose sum is σ = 134435006720. Its totient is φ = 32742835200.

The previous prime is 66615587771. The next prime is 66615587821. The reversal of 66615587776 is 67778551666.

It is a Harshad number since it is a multiple of its sum of digits (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66615587771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8737246 + ... + 8744866.

It is an arithmetic number, because the mean of its divisors is an integer number (2400625120).

Almost surely, 2^66615587776 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 66615587776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67217503360).

66615587776 is an abundant number, since it is smaller than the sum of its proper divisors (67819418944).

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

66615587776 is a wasteful number, since it uses less digits than its factorization.

66615587776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9933 (or 9923 counting only the distinct ones).

The product of its digits is 88905600, while the sum is 64.

The spelling of 66615587776 in words is "sixty-six billion, six hundred fifteen million, five hundred eighty-seven thousand, seven hundred seventy-six".