20565191 has 2 divisors, whose sum is σ = 20565192. Its totient is φ = 20565190.

The previous prime is 20565173. The next prime is 20565199. The reversal of 20565191 is 19156502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20565191 - 2¹⁴ = 20548807 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20565199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10282595 + 10282596.

It is an arithmetic number, because the mean of its divisors is an integer number (10282596).

Almost surely, 2^20565191 is an apocalyptic number.

20565191 is a deficient number, since it is larger than the sum of its proper divisors (1).

20565191 is an equidigital number, since it uses as much as digits as its factorization.

20565191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2700, while the sum is 29.

The square root of 20565191 is about 4534.8859963620. The cubic root of 20565191 is about 273.9749875049.

The spelling of 20565191 in words is "twenty million, five hundred sixty-five thousand, one hundred ninety-one".