21211120 has 80 divisors (see below), whose sum is σ = 57585600. Its totient is φ = 7262976.

The previous prime is 21211109. The next prime is 21211139. The reversal of 21211120 is 2111212.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21211120² = 899823223308800, 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 = 21211097 and 21211106.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27054 + ... + 27826.

It is an arithmetic number, because the mean of its divisors is an integer number (719820).

Almost surely, 2^21211120 is an apocalyptic number.

21211120 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 21211120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28792800).

21211120 is an abundant number, since it is smaller than the sum of its proper divisors (36374480).

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

21211120 is an equidigital number, since it uses as much as digits as its factorization.

21211120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 807 (or 787 counting only the distinct ones).

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

The square root of 21211120 is about 4605.5531698158. The cubic root of 21211120 is about 276.8138827167.

Adding to 21211120 its reverse (2111212), we get a palindrome (23322332).

The spelling of 21211120 in words is "twenty-one million, two hundred eleven thousand, one hundred twenty".