21203316 has 48 divisors (see below), whose sum is σ = 57870400. Its totient is φ = 6695136.

The previous prime is 21203293. The next prime is 21203317. The reversal of 21203316 is 61330212.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203317) 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 15 ways as a sum of consecutive naturals, for example, 3115 + ... + 7218.

Almost surely, 2^21203316 is an apocalyptic number.

It is an amenable number.

21203316 is an abundant number, since it is smaller than the sum of its proper divisors (36667084).

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

21203316 is a wasteful number, since it uses less digits than its factorization.

21203316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10365 (or 10357 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21203316 is about 4604.7058537978. The cubic root of 21203316 is about 276.7799300772.

Adding to 21203316 its reverse (61330212), we get a palindrome (82533528).

The spelling of 21203316 in words is "twenty-one million, two hundred three thousand, three hundred sixteen".