21668746129 has 2 divisors, whose sum is σ = 21668746130. Its totient is φ = 21668746128.

The previous prime is 21668746117. The next prime is 21668746133. The reversal of 21668746129 is 92164786612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20078890000 + 1589856129 = 141700^2 + 39873^2 .

It is a cyclic number.

It is not a de Polignac number, because 21668746129 - 2¹¹ = 21668744081 is a prime.

It is not a weakly prime, because it can be changed into another prime (21668746109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10834373064 + 10834373065.

It is an arithmetic number, because the mean of its divisors is an integer number (10834373065).

Almost surely, 2^21668746129 is an apocalyptic number.

It is an amenable number.

21668746129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21668746129 is an equidigital number, since it uses as much as digits as its factorization.

21668746129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1741824, while the sum is 52.

The spelling of 21668746129 in words is "twenty-one billion, six hundred sixty-eight million, seven hundred forty-six thousand, one hundred twenty-nine".