21121111120 has 20 divisors (see below), whose sum is σ = 49106583540. Its totient is φ = 8448444416.

The previous prime is 21121111087. The next prime is 21121111127. The reversal of 21121111120 is 2111112112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12904051216 + 8217059904 = 113596^2 + 90648^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×21121111120² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121111120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121111127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132006865 + ... + 132007024.

It is an arithmetic number, because the mean of its divisors is an integer number (2455329177).

Almost surely, 2^21121111120 is an apocalyptic number.

21121111120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121111120 is an abundant number, since it is smaller than the sum of its proper divisors (27985472420).

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

21121111120 is a wasteful number, since it uses less digits than its factorization.

21121111120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264013902 (or 264013896 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21121111120 its reverse (2111112112), we get a palindrome (23232223232).

The spelling of 21121111120 in words is "twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, one hundred twenty".