20129 has 2 divisors, whose sum is σ = 20130. Its totient is φ = 20128.

The previous prime is 20123. The next prime is 20143. The reversal of 20129 is 92102.

It is an a-pointer prime, because the next prime (20143) can be obtained adding 20129 to its sum of digits (14).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19600 + 529 = 140^2 + 23^2 .

It is a cyclic number.

It is not a de Polignac number, because 20129 - 2⁴ = 20113 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10064 + 10065.

It is an arithmetic number, because the mean of its divisors is an integer number (10065).

2²⁰¹²⁹ is an apocalyptic number.

It is an amenable number.

20129 is a deficient number, since it is larger than the sum of its proper divisors (1).

20129 is an equidigital number, since it uses as much as digits as its factorization.

20129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 20129 is about 141.8767070382. The cubic root of 20129 is about 27.2024111184.

The spelling of 20129 in words is "twenty thousand, one hundred twenty-nine".