20185729 has 4 divisors (see below), whose sum is σ = 20527920. Its totient is φ = 19843540.

The previous prime is 20185727. The next prime is 20185747. The reversal of 20185729 is 92758102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20185729 - 2¹ = 20185727 is a prime.

It is a super-2 number, since 2×20185729² = 814927310522882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20185694 and 20185703.

It is not an unprimeable number, because it can be changed into a prime (20185723) 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 in 3 ways as a sum of consecutive naturals, for example, 171007 + ... + 171124.

It is an arithmetic number, because the mean of its divisors is an integer number (5131980).

Almost surely, 2^20185729 is an apocalyptic number.

It is an amenable number.

20185729 is a deficient number, since it is larger than the sum of its proper divisors (342191).

20185729 is an equidigital number, since it uses as much as digits as its factorization.

20185729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342190.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 20185729 is about 4492.8531024283. The cubic root of 20185729 is about 272.2794174853.

The spelling of 20185729 in words is "twenty million, one hundred eighty-five thousand, seven hundred twenty-nine".