20505142129 has 2 divisors, whose sum is σ = 20505142130. Its totient is φ = 20505142128.

The previous prime is 20505142121. The next prime is 20505142181. The reversal of 20505142129 is 92124150502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11605106529 + 8900035600 = 107727^2 + 94340^2 .

It is a cyclic number.

It is not a de Polignac number, because 20505142129 - 2³ = 20505142121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20505142129.

It is not a weakly prime, because it can be changed into another prime (20505142121) 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, 10252571064 + 10252571065.

It is an arithmetic number, because the mean of its divisors is an integer number (10252571065).

Almost surely, 2^20505142129 is an apocalyptic number.

It is an amenable number.

20505142129 is a deficient number, since it is larger than the sum of its proper divisors (1).

20505142129 is an equidigital number, since it uses as much as digits as its factorization.

20505142129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 20505142129 in words is "twenty billion, five hundred five million, one hundred forty-two thousand, one hundred twenty-nine".