21112055544 has 96 divisors (see below), whose sum is σ = 54326603520. Its totient is φ = 6836832000.

The previous prime is 21112055533. The next prime is 21112055551. The reversal of 21112055544 is 44555021112.

It is a super-2 number, since 2×21112055544² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 10932259 + ... + 10934189.

It is an arithmetic number, because the mean of its divisors is an integer number (565902120).

Almost surely, 2^21112055544 is an apocalyptic number.

21112055544 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 21112055544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27163301760).

21112055544 is an abundant number, since it is smaller than the sum of its proper divisors (33214547976).

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

21112055544 is a wasteful number, since it uses less digits than its factorization.

21112055544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2293 (or 2248 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 30.

Adding to 21112055544 its reverse (44555021112), we get a palindrome (65667076656).

The spelling of 21112055544 in words is "twenty-one billion, one hundred twelve million, fifty-five thousand, five hundred forty-four".