21103420 has 48 divisors (see below), whose sum is σ = 49815360. Its totient is φ = 7451136.

The previous prime is 21103403. The next prime is 21103441. The reversal of 21103420 is 2430112.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 21103420.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4216 + ... + 7744.

It is an arithmetic number, because the mean of its divisors is an integer number (1037820).

Almost surely, 2^21103420 is an apocalyptic number.

21103420 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 21103420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24907680).

21103420 is an abundant number, since it is smaller than the sum of its proper divisors (28711940).

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

21103420 is a wasteful number, since it uses less digits than its factorization.

21103420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3574 (or 3572 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21103420 is about 4593.8458833531. The cubic root of 21103420 is about 276.3445776777.

Adding to 21103420 its reverse (2430112), we get a palindrome (23533532).

The spelling of 21103420 in words is "twenty-one million, one hundred three thousand, four hundred twenty".