21210002123 has 2 divisors, whose sum is σ = 21210002124. Its totient is φ = 21210002122.

The previous prime is 21210002117. The next prime is 21210002129. The reversal of 21210002123 is 32120001212.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21210002117) and next prime (21210002129).

It is a cyclic number.

It is not a de Polignac number, because 21210002123 - 2⁶ = 21210002059 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210002098 and 21210002107.

It is not a weakly prime, because it can be changed into another prime (21210002129) 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, 10605001061 + 10605001062.

It is an arithmetic number, because the mean of its divisors is an integer number (10605001062).

Almost surely, 2^21210002123 is an apocalyptic number.

21210002123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210002123 is an equidigital number, since it uses as much as digits as its factorization.

21210002123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21210002123 its reverse (32120001212), we get a palindrome (53330003335).

The spelling of 21210002123 in words is "twenty-one billion, two hundred ten million, two thousand, one hundred twenty-three".