21104404 has 6 divisors (see below), whose sum is σ = 36932714. Its totient is φ = 10552200.

The previous prime is 21104401. The next prime is 21104407. The reversal of 21104404 is 40440112.

It is an interprime number because it is at equal distance from previous prime (21104401) and next prime (21104407).

It can be written as a sum of positive squares in only one way, i.e., 20611600 + 492804 = 4540^2 + 702^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2638047 + ... + 2638054.

Almost surely, 2^21104404 is an apocalyptic number.

It is an amenable number.

21104404 is a deficient number, since it is larger than the sum of its proper divisors (15828310).

21104404 is a wasteful number, since it uses less digits than its factorization.

21104404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5276105 (or 5276103 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21104404 is about 4593.9529819100. The cubic root of 21104404 is about 276.3488726977.

Adding to 21104404 its reverse (40440112), we get a palindrome (61544516).

The spelling of 21104404 in words is "twenty-one million, one hundred four thousand, four hundred four".