20530523561 has 2 divisors, whose sum is σ = 20530523562. Its totient is φ = 20530523560.

The previous prime is 20530523437. The next prime is 20530523593. The reversal of 20530523561 is 16532503502.

It is an a-pointer prime, because the next prime (20530523593) can be obtained adding 20530523561 to its sum of digits (32).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20401837225 + 128686336 = 142835^2 + 11344^2 .

It is a cyclic number.

It is not a de Polignac number, because 20530523561 - 2¹⁴ = 20530507177 is a prime.

It is a super-2 number, since 2×20530523561² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20530523261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10265261780 + 10265261781.

It is an arithmetic number, because the mean of its divisors is an integer number (10265261781).

Almost surely, 2^20530523561 is an apocalyptic number.

It is an amenable number.

20530523561 is a deficient number, since it is larger than the sum of its proper divisors (1).

20530523561 is an equidigital number, since it uses as much as digits as its factorization.

20530523561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27000, while the sum is 32.

The spelling of 20530523561 in words is "twenty billion, five hundred thirty million, five hundred twenty-three thousand, five hundred sixty-one".