21131313 has 8 divisors (see below), whose sum is σ = 32200128. Its totient is φ = 12075024.

The previous prime is 21131293. The next prime is 21131317. The reversal of 21131313 is 31313112.

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

It is not a de Polignac number, because 21131313 - 2⁹ = 21130801 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21131292 and 21131301.

It is not an unprimeable number, because it can be changed into a prime (21131317) 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, 503106 + ... + 503147.

It is an arithmetic number, because the mean of its divisors is an integer number (4025016).

Almost surely, 2^21131313 is an apocalyptic number.

It is an amenable number.

21131313 is a deficient number, since it is larger than the sum of its proper divisors (11068815).

21131313 is a wasteful number, since it uses less digits than its factorization.

21131313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1006263.

The product of its digits is 54, while the sum is 15.

The square root of 21131313 is about 4596.8807902751. The cubic root of 21131313 is about 276.4662749476.

Adding to 21131313 its reverse (31313112), we get a palindrome (52444425).

The spelling of 21131313 in words is "twenty-one million, one hundred thirty-one thousand, three hundred thirteen".