21121100000 has 576 divisors, whose sum is σ = 70114512384. Its totient is φ = 6048000000.

The previous prime is 21121099991. The next prime is 21121100047. The reversal of 21121100000 is 112112.

It is a super-2 number, since 2×21121100000² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (8).

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 95 ways as a sum of consecutive naturals, for example, 100099895 + ... + 100100105.

It is an arithmetic number, because the mean of its divisors is an integer number (121726584).

Almost surely, 2^21121100000 is an apocalyptic number.

21121100000 is a gapful number since it is divisible by the number (20) 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 21121100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35057256192).

21121100000 is an abundant number, since it is smaller than the sum of its proper divisors (48993412384).

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

21121100000 is a wasteful number, since it uses less digits than its factorization.

21121100000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277 (or 249 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21121100000 its reverse (112112), we get a palindrome (21121212112).

It can be divided in two parts, 21121 and 100000, that added together give a palindrome (121121).

The spelling of 21121100000 in words is "twenty-one billion, one hundred twenty-one million, one hundred thousand".