20785189 has 4 divisors (see below), whose sum is σ = 20795500. Its totient is φ = 20774880.

The previous prime is 20785187. The next prime is 20785207. The reversal of 20785189 is 98158702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 98158702 = 2 ⋅49079351.

It can be written as a sum of positive squares in 2 ways, for example, as 3629025 + 17156164 = 1905^2 + 4142^2 .

It is a cyclic number.

It is not a de Polignac number, because 20785189 - 2¹ = 20785187 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20785181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1032 + ... + 6529.

It is an arithmetic number, because the mean of its divisors is an integer number (5198875).

Almost surely, 2^20785189 is an apocalyptic number.

It is an amenable number.

20785189 is a deficient number, since it is larger than the sum of its proper divisors (10311).

20785189 is an equidigital number, since it uses as much as digits as its factorization.

20785189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10310.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 20785189 is about 4559.0776479459. The cubic root of 20785189 is about 274.9484818093.

The spelling of 20785189 in words is "twenty million, seven hundred eighty-five thousand, one hundred eighty-nine".