21202304243 has 4 divisors (see below), whose sum is σ = 21389935368. Its totient is φ = 21014673120.

The previous prime is 21202304237. The next prime is 21202304303. The reversal of 21202304243 is 34240320212.

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-21202304243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21202304203) 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, 93815393 + ... + 93815618.

It is an arithmetic number, because the mean of its divisors is an integer number (5347483842).

Almost surely, 2^21202304243 is an apocalyptic number.

21202304243 is a deficient number, since it is larger than the sum of its proper divisors (187631125).

21202304243 is a wasteful number, since it uses less digits than its factorization.

21202304243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187631124.

The product of its (nonzero) digits is 2304, while the sum is 23.

Adding to 21202304243 its reverse (34240320212), we get a palindrome (55442624455).

The spelling of 21202304243 in words is "twenty-one billion, two hundred two million, three hundred four thousand, two hundred forty-three".