21131103 has 24 divisors (see below), whose sum is σ = 33547008. Its totient is φ = 11790576.

The previous prime is 21131087. The next prime is 21131137. The reversal of 21131103 is 30113112.

It is not a de Polignac number, because 21131103 - 2⁴ = 21131087 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131183) 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, 4650 + ... + 7992.

It is an arithmetic number, because the mean of its divisors is an integer number (1397792).

Almost surely, 2^21131103 is an apocalyptic number.

21131103 is a deficient number, since it is larger than the sum of its proper divisors (12415905).

21131103 is a wasteful number, since it uses less digits than its factorization.

21131103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3403 (or 3396 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 21131103 is about 4596.8579486427. The cubic root of 21131103 is about 276.4653591170.

Adding to 21131103 its reverse (30113112), we get a palindrome (51244215).

Subtracting 21131103 from its reverse (30113112), we obtain a square (8982009 = 2997²).

The spelling of 21131103 in words is "twenty-one million, one hundred thirty-one thousand, one hundred three".