65505521664 has 624 divisors, whose sum is σ = 222111611904. Its totient is φ = 19110297600.

The previous prime is 65505521663. The next prime is 65505521681. The reversal of 65505521664 is 46612550556.

65505521664 is a `hidden beast` number, since 65 + 5 + 0 + 5 + 521 + 6 + 64 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65505521663) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 339406752 + ... + 339406944.

It is an arithmetic number, because the mean of its divisors is an integer number (355948096).

Almost surely, 2^65505521664 is an apocalyptic number.

65505521664 is a gapful number since it is divisible by the number (64) 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 65505521664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111055805952).

65505521664 is an abundant number, since it is smaller than the sum of its proper divisors (156606090240).

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

65505521664 is a wasteful number, since it uses less digits than its factorization.

65505521664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 1080000, while the sum is 45.

The spelling of 65505521664 in words is "sixty-five billion, five hundred five million, five hundred twenty-one thousand, six hundred sixty-four".