20309129 has 2 divisors, whose sum is σ = 20309130. Its totient is φ = 20309128.

The previous prime is 20309087. The next prime is 20309131. The reversal of 20309129 is 92190302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18292729 + 2016400 = 4277^2 + 1420^2 .

It is a cyclic number.

It is not a de Polignac number, because 20309129 - 2¹⁶ = 20243593 is a prime.

Together with 20309131, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20309098 and 20309107.

It is not a weakly prime, because it can be changed into another prime (20306129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10154564 + 10154565.

It is an arithmetic number, because the mean of its divisors is an integer number (10154565).

Almost surely, 2^20309129 is an apocalyptic number.

It is an amenable number.

20309129 is a deficient number, since it is larger than the sum of its proper divisors (1).

20309129 is an equidigital number, since it uses as much as digits as its factorization.

20309129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 20309129 is about 4506.5650999403. The cubic root of 20309129 is about 272.8331262465.

The spelling of 20309129 in words is "twenty million, three hundred nine thousand, one hundred twenty-nine".