20138191 has 2 divisors, whose sum is σ = 20138192. Its totient is φ = 20138190.

The previous prime is 20138171. The next prime is 20138197. The reversal of 20138191 is 19183102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20138191 - 2⁵ = 20138159 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20138197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10069095 + 10069096.

It is an arithmetic number, because the mean of its divisors is an integer number (10069096).

Almost surely, 2^20138191 is an apocalyptic number.

20138191 is a deficient number, since it is larger than the sum of its proper divisors (1).

20138191 is an equidigital number, since it uses as much as digits as its factorization.

20138191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 20138191 is about 4487.5595817772. The cubic root of 20138191 is about 272.0655073984.

The spelling of 20138191 in words is "twenty million, one hundred thirty-eight thousand, one hundred ninety-one".