21243113 has 4 divisors (see below), whose sum is σ = 21272448. Its totient is φ = 21213780.

The previous prime is 21243077. The next prime is 21243137. The reversal of 21243113 is 31134212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21243113 - 2⁶ = 21243049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21243091 and 21243100.

It is not an unprimeable number, because it can be changed into a prime (21243193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13553 + ... + 15038.

It is an arithmetic number, because the mean of its divisors is an integer number (5318112).

Almost surely, 2^21243113 is an apocalyptic number.

It is an amenable number.

21243113 is a deficient number, since it is larger than the sum of its proper divisors (29335).

21243113 is an equidigital number, since it uses as much as digits as its factorization.

21243113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29334.

The product of its digits is 144, while the sum is 17.

The square root of 21243113 is about 4609.0251680806. The cubic root of 21243113 is about 276.9529867603.

Adding to 21243113 its reverse (31134212), we get a palindrome (52377325).

The spelling of 21243113 in words is "twenty-one million, two hundred forty-three thousand, one hundred thirteen".