216561501335550 has 192 divisors, whose sum is σ = 623979543610368. Its totient is φ = 48685104000000.

The previous prime is 216561501335513. The next prime is 216561501335603. The reversal of 216561501335550 is 55533105165612.

It is a super-3 number, since 3×216561501335550³ (a number of 44 digits) contains 333 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 216561501335550.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9251730 + ... + 22775370.

It is an arithmetic number, because the mean of its divisors is an integer number (3249893456304).

Almost surely, 2^{216561501335550} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216561501335550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (311989771805184).

216561501335550 is an abundant number, since it is smaller than the sum of its proper divisors (407418042274818).

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

216561501335550 is a wasteful number, since it uses less digits than its factorization.

216561501335550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13523915 (or 13523910 counting only the distinct ones).

The product of its (nonzero) digits is 2025000, while the sum is 48.

The spelling of 216561501335550 in words is "two hundred sixteen trillion, five hundred sixty-one billion, five hundred one million, three hundred thirty-five thousand, five hundred fifty".