2181997806336 has 144 divisors (see below), whose sum is σ = 6453282215520. Its totient is φ = 727250227200.

The previous prime is 2181997806311. The next prime is 2181997806361. The reversal of 2181997806336 is 6336087991812.

2181997806336 is a `hidden beast` number, since 218 + 1 + 9 + 9 + 7 + 80 + 6 + 336 = 666.

It is an interprime number because it is at equal distance from previous prime (2181997806311) and next prime (2181997806361).

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-3 number, since 3×2181997806336³ (a number of 38 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109897786 + ... + 109917638.

It is an arithmetic number, because the mean of its divisors is an integer number (44814459830).

Almost surely, 2^{2181997806336} 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 2181997806336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3226641107760).

2181997806336 is an abundant number, since it is smaller than the sum of its proper divisors (4271284409184).

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

2181997806336 is a wasteful number, since it uses less digits than its factorization.

2181997806336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35779 (or 35759 counting only the distinct ones).

The product of its (nonzero) digits is 23514624, while the sum is 63.

The spelling of 2181997806336 in words is "two trillion, one hundred eighty-one billion, nine hundred ninety-seven million, eight hundred six thousand, three hundred thirty-six".