21131211210203 has 4 divisors (see below), whose sum is σ = 21133049197800. Its totient is φ = 21129373222608.

The previous prime is 21131211210199. The next prime is 21131211210233. The reversal of 21131211210203 is 30201211213112.

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 21131211210203 - 2² = 21131211210199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21131211210233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 918976553 + ... + 918999546.

It is an arithmetic number, because the mean of its divisors is an integer number (5283262299450).

Almost surely, 2^{21131211210203} is an apocalyptic number.

21131211210203 is a deficient number, since it is larger than the sum of its proper divisors (1837987597).

21131211210203 is a wasteful number, since it uses less digits than its factorization.

21131211210203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1837987596.

The product of its (nonzero) digits is 144, while the sum is 20.

Adding to 21131211210203 its reverse (30201211213112), we get a palindrome (51332422423315).

The spelling of 21131211210203 in words is "twenty-one trillion, one hundred thirty-one billion, two hundred eleven million, two hundred ten thousand, two hundred three".