21106344 has 64 divisors (see below), whose sum is σ = 61165440. Its totient is φ = 5944320.

The previous prime is 21106343. The next prime is 21106361. The reversal of 21106344 is 44360112.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21106344.

It is not an unprimeable number, because it can be changed into a prime (21106343) 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, 11404 + ... + 13124.

It is an arithmetic number, because the mean of its divisors is an integer number (955710).

Almost surely, 2^21106344 is an apocalyptic number.

21106344 is a gapful number since it is divisible by the number (24) 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 21106344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30582720).

21106344 is an abundant number, since it is smaller than the sum of its proper divisors (40059096).

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

21106344 is a wasteful number, since it uses less digits than its factorization.

21106344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1810 (or 1806 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21106344 is about 4594.1641241906. The cubic root of 21106344 is about 276.3573401308.

Adding to 21106344 its reverse (44360112), we get a palindrome (65466456).

The spelling of 21106344 in words is "twenty-one million, one hundred six thousand, three hundred forty-four".