20565765511 has 2 divisors, whose sum is σ = 20565765512. Its totient is φ = 20565765510.

The previous prime is 20565765503. The next prime is 20565765529. The reversal of 20565765511 is 11556756502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20565765511 - 2³ = 20565765503 is a prime.

It is a super-2 number, since 2×20565765511² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20565765911) 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, 10282882755 + 10282882756.

It is an arithmetic number, because the mean of its divisors is an integer number (10282882756).

Almost surely, 2^20565765511 is an apocalyptic number.

20565765511 is a deficient number, since it is larger than the sum of its proper divisors (1).

20565765511 is an equidigital number, since it uses as much as digits as its factorization.

20565765511 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 315000, while the sum is 43.

Subtracting from 20565765511 its reverse (11556756502), we obtain a palindrome (9009009009).

The spelling of 20565765511 in words is "twenty billion, five hundred sixty-five million, seven hundred sixty-five thousand, five hundred eleven".