21121120 has 48 divisors (see below), whose sum is σ = 50431248. Its totient is φ = 8358400.

The previous prime is 21121099. The next prime is 21121129. The reversal of 21121120 is 2112112.

It is a super-2 number, since 2×21121120² = 892203420108800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21121097 and 21121106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15507 + ... + 16813.

It is an arithmetic number, because the mean of its divisors is an integer number (1050651).

Almost surely, 2^21121120 is an apocalyptic number.

21121120 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 21121120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25215624).

21121120 is an abundant number, since it is smaller than the sum of its proper divisors (29310128).

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

21121120 is a wasteful number, since it uses less digits than its factorization.

21121120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1423 (or 1415 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 21121120 is about 4595.7719699741. The cubic root of 21121120 is about 276.4218152719.

21121120 divided by its sum of digits (10) gives a palindrome (2112112).

Adding to 21121120 its reverse (2112112), we get a palindrome (23233232).

The spelling of 21121120 in words is "twenty-one million, one hundred twenty-one thousand, one hundred twenty".