21131104 has 12 divisors (see below), whose sum is σ = 41601924. Its totient is φ = 10565536.

The previous prime is 21131087. The next prime is 21131137. The reversal of 21131104 is 40113112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330142 + ... + 330205.

It is an arithmetic number, because the mean of its divisors is an integer number (3466827).

Almost surely, 2^21131104 is an apocalyptic number.

It is an amenable number.

21131104 is a deficient number, since it is larger than the sum of its proper divisors (20470820).

21131104 is an equidigital number, since it uses as much as digits as its factorization.

21131104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660357 (or 660349 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 21131104 is about 4596.8580574127. The cubic root of 21131104 is about 276.4653634781.

Adding to 21131104 its reverse (40113112), we get a palindrome (61244216).

The spelling of 21131104 in words is "twenty-one million, one hundred thirty-one thousand, one hundred four".