2181997985832 has 256 divisors, whose sum is σ = 7532678592000. Its totient is φ = 570897248256.

The previous prime is 2181997985819. The next prime is 2181997985879. The reversal of 2181997985832 is 2385897991812.

2181997985832 is a `hidden beast` number, since 21 + 8 + 19 + 9 + 7 + 9 + 8 + 583 + 2 = 666.

It is a super-2 number, since 2×2181997985832² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 196107 + ... + 2098202.

It is an arithmetic number, because the mean of its divisors is an integer number (29424525750).

Almost surely, 2^{2181997985832} 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 2181997985832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3766339296000).

2181997985832 is an abundant number, since it is smaller than the sum of its proper divisors (5350680606168).

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

2181997985832 is a wasteful number, since it uses less digits than its factorization.

2181997985832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2294385 (or 2294375 counting only the distinct ones).

The product of its digits is 156764160, while the sum is 72.

The spelling of 2181997985832 in words is "two trillion, one hundred eighty-one billion, nine hundred ninety-seven million, nine hundred eighty-five thousand, eight hundred thirty-two".