21103842 has 16 divisors (see below), whose sum is σ = 42269472. Its totient is φ = 7024320.

The previous prime is 21103759. The next prime is 21103843. The reversal of 21103842 is 24830112.

It is not an unprimeable number, because it can be changed into a prime (21103843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2698 + ... + 7034.

It is an arithmetic number, because the mean of its divisors is an integer number (2641842).

Almost surely, 2^21103842 is an apocalyptic number.

21103842 is an abundant number, since it is smaller than the sum of its proper divisors (21165630).

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

21103842 is a wasteful number, since it uses less digits than its factorization.

21103842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5153.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21103842 is about 4593.8918141376. The cubic root of 21103842 is about 276.3464196640.

Adding to 21103842 its reverse (24830112), we get a palindrome (45933954).

It can be divided in two parts, 21103 and 842, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21103842 in words is "twenty-one million, one hundred three thousand, eight hundred forty-two".