21121120111100 has 144 divisors (see below), whose sum is σ = 46899323563680. Its totient is φ = 8254574592000.

The previous prime is 21121120111097. The next prime is 21121120111103. The reversal of 21121120111100 is 111102112112.

It is an interprime number because it is at equal distance from previous prime (21121120111097) and next prime (21121120111103).

It is a super-2 number, since 2×21121120111100² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121120111103) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 339924836 + ... + 339986964.

It is an arithmetic number, because the mean of its divisors is an integer number (325689746970).

Almost surely, 2^{21121120111100} is an apocalyptic number.

21121120111100 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 21121120111100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23449661781840).

21121120111100 is an abundant number, since it is smaller than the sum of its proper divisors (25778203452580).

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

21121120111100 is a wasteful number, since it uses less digits than its factorization.

21121120111100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62688 (or 62681 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21121120111100 its reverse (111102112112), we get a palindrome (21232222223212).

The spelling of 21121120111100 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred twenty million, one hundred eleven thousand, one hundred".