21203134243 has 2 divisors, whose sum is σ = 21203134244. Its totient is φ = 21203134242.

The previous prime is 21203134237. The next prime is 21203134279. The reversal of 21203134243 is 34243130212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21203134243 - 2¹³ = 21203126051 is a prime.

It is not a weakly prime, because it can be changed into another prime (21203134943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601567121 + 10601567122.

It is an arithmetic number, because the mean of its divisors is an integer number (10601567122).

Almost surely, 2^21203134243 is an apocalyptic number.

21203134243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203134243 is an equidigital number, since it uses as much as digits as its factorization.

21203134243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 25.

Adding to 21203134243 its reverse (34243130212), we get a palindrome (55446264455).

The spelling of 21203134243 in words is "twenty-one billion, two hundred three million, one hundred thirty-four thousand, two hundred forty-three".