21871161984 has 256 divisors, whose sum is σ = 68189921280. Its totient is φ = 6081503232.

The previous prime is 21871161959. The next prime is 21871161989. The reversal of 21871161984 is 48916117812.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (21871161989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29435917 + ... + 29436659.

It is an arithmetic number, because the mean of its divisors is an integer number (266366880).

Almost surely, 2^21871161984 is an apocalyptic number.

21871161984 is a gapful number since it is divisible by the number (24) 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 21871161984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34094960640).

21871161984 is an abundant number, since it is smaller than the sum of its proper divisors (46318759296).

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

21871161984 is a wasteful number, since it uses less digits than its factorization.

21871161984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1047 (or 1035 counting only the distinct ones).

The product of its digits is 193536, while the sum is 48.

The spelling of 21871161984 in words is "twenty-one billion, eight hundred seventy-one million, one hundred sixty-one thousand, nine hundred eighty-four".