20790191 has 2 divisors, whose sum is σ = 20790192. Its totient is φ = 20790190.

The previous prime is 20790173. The next prime is 20790233. The reversal of 20790191 is 19109702.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20790191 is a prime.

It is a Chen prime.

It is equal to p_1317539 and since 20790191 and 1317539 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20790391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10395095 + 10395096.

It is an arithmetic number, because the mean of its divisors is an integer number (10395096).

Almost surely, 2^20790191 is an apocalyptic number.

20790191 is a deficient number, since it is larger than the sum of its proper divisors (1).

20790191 is an equidigital number, since it uses as much as digits as its factorization.

20790191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1134, while the sum is 29.

The square root of 20790191 is about 4559.6261908187. The cubic root of 20790191 is about 274.9705356862.

Adding to 20790191 its reverse (19109702), we get a palindrome (39899893).

The spelling of 20790191 in words is "twenty million, seven hundred ninety thousand, one hundred ninety-one".