21312203 has 8 divisors (see below), whose sum is σ = 24617520. Its totient is φ = 18234880.

The previous prime is 21312173. The next prime is 21312223. The reversal of 21312203 is 30221312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21312203 - 2¹² = 21308107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21312223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56798 + ... + 57171.

It is an arithmetic number, because the mean of its divisors is an integer number (3077190).

Almost surely, 2^21312203 is an apocalyptic number.

21312203 is a deficient number, since it is larger than the sum of its proper divisors (3305317).

21312203 is a wasteful number, since it uses less digits than its factorization.

21312203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113997.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21312203 is about 4616.5141611393. The cubic root of 21312203 is about 277.2529110234.

Adding to 21312203 its reverse (30221312), we get a palindrome (51533515).

It can be divided in two parts, 2131 and 2203, that added together give a palindrome (4334).

The spelling of 21312203 in words is "twenty-one million, three hundred twelve thousand, two hundred three".