21313303243 has 4 divisors (see below), whose sum is σ = 21324945328. Its totient is φ = 21301661160.

The previous prime is 21313303163. The next prime is 21313303247. The reversal of 21313303243 is 34230331312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21313303243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21313303247) 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, 5818296 + ... + 5821957.

It is an arithmetic number, because the mean of its divisors is an integer number (5331236332).

Almost surely, 2^21313303243 is an apocalyptic number.

21313303243 is a deficient number, since it is larger than the sum of its proper divisors (11642085).

21313303243 is a wasteful number, since it uses less digits than its factorization.

21313303243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11642084.

The product of its (nonzero) digits is 3888, while the sum is 25.

Adding to 21313303243 its reverse (34230331312), we get a palindrome (55543634555).

The spelling of 21313303243 in words is "twenty-one billion, three hundred thirteen million, three hundred three thousand, two hundred forty-three".