21103911 has 24 divisors (see below), whose sum is σ = 31370976. Its totient is φ = 13665600.

The previous prime is 21103897. The next prime is 21103933. The reversal of 21103911 is 11930112.

It is not a de Polignac number, because 21103911 - 2⁵ = 21103879 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103961) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 71881 + ... + 72173.

It is an arithmetic number, because the mean of its divisors is an integer number (1307124).

Almost surely, 2^21103911 is an apocalyptic number.

21103911 is a deficient number, since it is larger than the sum of its proper divisors (10267065).

21103911 is a wasteful number, since it uses less digits than its factorization.

21103911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503 (or 500 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 18.

The square root of 21103911 is about 4593.8993241037. The cubic root of 21103911 is about 276.3467208395.

The spelling of 21103911 in words is "twenty-one million, one hundred three thousand, nine hundred eleven".