21201022123 has 2 divisors, whose sum is σ = 21201022124. Its totient is φ = 21201022122.

The previous prime is 21201022081. The next prime is 21201022147. The reversal of 21201022123 is 32122010212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201022123 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201022097 and 21201022106.

It is not a weakly prime, because it can be changed into another prime (21201092123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600511061 + 10600511062.

It is an arithmetic number, because the mean of its divisors is an integer number (10600511062).

Almost surely, 2^21201022123 is an apocalyptic number.

21201022123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201022123 is an equidigital number, since it uses as much as digits as its factorization.

21201022123 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 21201022123 its reverse (32122010212), we get a palindrome (53323032335).

The spelling of 21201022123 in words is "twenty-one billion, two hundred one million, twenty-two thousand, one hundred twenty-three".