21121888188 has 48 divisors (see below), whose sum is σ = 51059746080. Its totient is φ = 6787732224.

The previous prime is 21121888171. The next prime is 21121888189. The reversal of 21121888188 is 88188812112.

It is a super-2 number, since 2×21121888188² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121888189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 190770 + ... + 280422.

It is an arithmetic number, because the mean of its divisors is an integer number (1063744710).

Almost surely, 2^21121888188 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 21121888188, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25529873040).

21121888188 is an abundant number, since it is smaller than the sum of its proper divisors (29937857892).

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

21121888188 is a wasteful number, since it uses less digits than its factorization.

21121888188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90366 (or 90364 counting only the distinct ones).

The product of its digits is 131072, while the sum is 48.

The spelling of 21121888188 in words is "twenty-one billion, one hundred twenty-one million, eight hundred eighty-eight thousand, one hundred eighty-eight".