21243123432203 has 4 divisors (see below), whose sum is σ = 21247559253120. Its totient is φ = 21238687611288.

The previous prime is 21243123432131. The next prime is 21243123432229. The reversal of 21243123432203 is 30223432134212.

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

It is a cyclic number.

It is not a de Polignac number, because 21243123432203 - 2³⁸ = 20968245525259 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21243123432203.

It is not an unprimeable number, because it can be changed into a prime (21243123432253) 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, 2217903275 + ... + 2217912852.

It is an arithmetic number, because the mean of its divisors is an integer number (5311889813280).

Almost surely, 2^{21243123432203} is an apocalyptic number.

21243123432203 is a deficient number, since it is larger than the sum of its proper divisors (4435820917).

21243123432203 is an equidigital number, since it uses as much as digits as its factorization.

21243123432203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4435820916.

The product of its (nonzero) digits is 41472, while the sum is 32.

Adding to 21243123432203 its reverse (30223432134212), we get a palindrome (51466555566415).

The spelling of 21243123432203 in words is "twenty-one trillion, two hundred forty-three billion, one hundred twenty-three million, four hundred thirty-two thousand, two hundred three".