21043212103 has 2 divisors, whose sum is σ = 21043212104. Its totient is φ = 21043212102.

The previous prime is 21043212089. The next prime is 21043212109. The reversal of 21043212103 is 30121234012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21043212103 - 2⁹ = 21043211591 is a prime.

It is a super-2 number, since 2×21043212103² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21043212109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521606051 + 10521606052.

It is an arithmetic number, because the mean of its divisors is an integer number (10521606052).

Almost surely, 2^21043212103 is an apocalyptic number.

21043212103 is a deficient number, since it is larger than the sum of its proper divisors (1).

21043212103 is an equidigital number, since it uses as much as digits as its factorization.

21043212103 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21043212103 its reverse (30121234012), we get a palindrome (51164446115).

The spelling of 21043212103 in words is "twenty-one billion, forty-three million, two hundred twelve thousand, one hundred three".