21104220 has 48 divisors (see below), whose sum is σ = 59407488. Its totient is φ = 5597760.

The previous prime is 21104203. The next prime is 21104221. The reversal of 21104220 is 2240112.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21104196 and 21104205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11827 + ... + 13493.

It is an arithmetic number, because the mean of its divisors is an integer number (1237656).

Almost surely, 2^21104220 is an apocalyptic number.

21104220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21104220 is an abundant number, since it is smaller than the sum of its proper divisors (38303268).

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

21104220 is a wasteful number, since it uses less digits than its factorization.

21104220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1890 (or 1888 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21104220 is about 4593.9329555404. The cubic root of 21104220 is about 276.3480695741.

Adding to 21104220 its reverse (2240112), we get a palindrome (23344332).

The spelling of 21104220 in words is "twenty-one million, one hundred four thousand, two hundred twenty".