21203404 has 6 divisors (see below), whose sum is σ = 37105964. Its totient is φ = 10601700.

The previous prime is 21203383. The next prime is 21203407. The reversal of 21203404 is 40430212.

It is not an unprimeable number, because it can be changed into a prime (21203407) by changing a digit.

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, 2650422 + ... + 2650429.

Almost surely, 2^21203404 is an apocalyptic number.

It is an amenable number.

21203404 is a deficient number, since it is larger than the sum of its proper divisors (15902560).

21203404 is a wasteful number, since it uses less digits than its factorization.

21203404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5300855 (or 5300853 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21203404 is about 4604.7154092300. The cubic root of 21203404 is about 276.7803129827.

Adding to 21203404 its reverse (40430212), we get a palindrome (61633616).

The spelling of 21203404 in words is "twenty-one million, two hundred three thousand, four hundred four".