21212313 has 8 divisors (see below), whose sum is σ = 28313376. Its totient is φ = 14126400.

The previous prime is 21212297. The next prime is 21212353. The reversal of 21212313 is 31321212.

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

It is not a de Polignac number, because 21212313 - 2⁴ = 21212297 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21212292 and 21212301.

It is not an unprimeable number, because it can be changed into a prime (21212353) 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, 33 + ... + 6513.

It is an arithmetic number, because the mean of its divisors is an integer number (3539172).

Almost surely, 2^21212313 is an apocalyptic number.

It is an amenable number.

21212313 is a deficient number, since it is larger than the sum of its proper divisors (7101063).

21212313 is a wasteful number, since it uses less digits than its factorization.

21212313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7575.

The product of its digits is 72, while the sum is 15.

The square root of 21212313 is about 4605.6826855527. The cubic root of 21212313 is about 276.8190723337.

Adding to 21212313 its reverse (31321212), we get a palindrome (52533525).

The spelling of 21212313 in words is "twenty-one million, two hundred twelve thousand, three hundred thirteen".