21212120023 has 2 divisors, whose sum is σ = 21212120024. Its totient is φ = 21212120022.

The previous prime is 21212119997. The next prime is 21212120029. The reversal of 21212120023 is 32002121212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21212120023 - 2¹³ = 21212111831 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21212119979 and 21212120006.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212120029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606060011 + 10606060012.

It is an arithmetic number, because the mean of its divisors is an integer number (10606060012).

Almost surely, 2^21212120023 is an apocalyptic number.

21212120023 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212120023 is an equidigital number, since it uses as much as digits as its factorization.

21212120023 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21212120023 its reverse (32002121212), we get a palindrome (53214241235).

The spelling of 21212120023 in words is "twenty-one billion, two hundred twelve million, one hundred twenty thousand, twenty-three".