20700191 has 2 divisors, whose sum is σ = 20700192. Its totient is φ = 20700190.

The previous prime is 20700187. The next prime is 20700193. The reversal of 20700191 is 19100702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20700191 - 2² = 20700187 is a prime.

It is a Sophie Germain prime.

Together with 20700193, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20700193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10350095 + 10350096.

It is an arithmetic number, because the mean of its divisors is an integer number (10350096).

Almost surely, 2^20700191 is an apocalyptic number.

20700191 is a deficient number, since it is larger than the sum of its proper divisors (1).

20700191 is an equidigital number, since it uses as much as digits as its factorization.

20700191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 126, while the sum is 20.

The square root of 20700191 is about 4549.7462566609. The cubic root of 20700191 is about 274.5731825230.

Adding to 20700191 its reverse (19100702), we get a palindrome (39800893).

The spelling of 20700191 in words is "twenty million, seven hundred thousand, one hundred ninety-one".