65561116566 has 64 divisors (see below), whose sum is σ = 144589142016. Its totient is φ = 19652544000.

The previous prime is 65561116549. The next prime is 65561116571. The reversal of 65561116566 is 66561116556.

It is a Curzon number.

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, 8642011 + ... + 8649593.

It is an arithmetic number, because the mean of its divisors is an integer number (2259205344).

Almost surely, 2^65561116566 is an apocalyptic number.

65561116566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 65561116566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72294571008).

65561116566 is an abundant number, since it is smaller than the sum of its proper divisors (79028025450).

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

65561116566 is a wasteful number, since it uses less digits than its factorization.

65561116566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8997.

The product of its digits is 972000, while the sum is 48.

The spelling of 65561116566 in words is "sixty-five billion, five hundred sixty-one million, one hundred sixteen thousand, five hundred sixty-six".