21212303 has 8 divisors (see below), whose sum is σ = 25518720. Its totient is φ = 17224920.

The previous prime is 21212297. The next prime is 21212353. The reversal of 21212303 is 30321212.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21212303 - 2⁶ = 21212239 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79613 + ... + 79878.

It is an arithmetic number, because the mean of its divisors is an integer number (3189840).

Almost surely, 2^21212303 is an apocalyptic number.

21212303 is a deficient number, since it is larger than the sum of its proper divisors (4306417).

21212303 is a wasteful number, since it uses less digits than its factorization.

21212303 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159517.

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

The square root of 21212303 is about 4605.6815999372. The cubic root of 21212303 is about 276.8190288340.

Adding to 21212303 its reverse (30321212), we get a palindrome (51533515).

The spelling of 21212303 in words is "twenty-one million, two hundred twelve thousand, three hundred three".