21203412 has 24 divisors (see below), whose sum is σ = 49867776. Its totient is φ = 7011648.

The previous prime is 21203407. The next prime is 21203419. The reversal of 21203412 is 21430212.

It is a junction number, because it is equal to n+sod(n) for n = 21203391 and 21203400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203419) 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 in 7 ways as a sum of consecutive naturals, for example, 5433 + ... + 8480.

It is an arithmetic number, because the mean of its divisors is an integer number (2077824).

Almost surely, 2^21203412 is an apocalyptic number.

It is an amenable number.

21203412 is an abundant number, since it is smaller than the sum of its proper divisors (28664364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21203412 is a wasteful number, since it uses less digits than its factorization.

21203412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14047 (or 14045 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21203412 is about 4604.7162779046. The cubic root of 21203412 is about 276.7803477923.

Adding to 21203412 its reverse (21430212), we get a palindrome (42633624).

The spelling of 21203412 in words is "twenty-one million, two hundred three thousand, four hundred twelve".