20185129 has 2 divisors, whose sum is σ = 20185130. Its totient is φ = 20185128.

The previous prime is 20185117. The next prime is 20185133. The reversal of 20185129 is 92158102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11022400 + 9162729 = 3320^2 + 3027^2 .

It is a cyclic number.

It is not a de Polignac number, because 20185129 - 2⁵ = 20185097 is a prime.

It is a super-3 number, since 3×20185129³ (a number of 23 digits) contains 333 as substring.

It is equal to p_1281655 and since 20185129 and 1281655 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 20185097 and 20185106.

It is not a weakly prime, because it can be changed into another prime (20185159) 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, 10092564 + 10092565.

It is an arithmetic number, because the mean of its divisors is an integer number (10092565).

Almost surely, 2^20185129 is an apocalyptic number.

It is an amenable number.

20185129 is a deficient number, since it is larger than the sum of its proper divisors (1).

20185129 is an equidigital number, since it uses as much as digits as its factorization.

20185129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 20185129 is about 4492.7863292171. The cubic root of 20185129 is about 272.2767197168.

The spelling of 20185129 in words is "twenty million, one hundred eighty-five thousand, one hundred twenty-nine".