20135441561 has 2 divisors, whose sum is σ = 20135441562. Its totient is φ = 20135441560.

The previous prime is 20135441533. The next prime is 20135441581. The reversal of 20135441561 is 16514453102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20119720336 + 15721225 = 141844^2 + 3965^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20135441561 is a prime.

It is a super-2 number, since 2×20135441561² (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 (20135441581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10067720780 + 10067720781.

It is an arithmetic number, because the mean of its divisors is an integer number (10067720781).

Almost surely, 2^20135441561 is an apocalyptic number.

It is an amenable number.

20135441561 is a deficient number, since it is larger than the sum of its proper divisors (1).

20135441561 is an equidigital number, since it uses as much as digits as its factorization.

20135441561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14400, while the sum is 32.

Adding to 20135441561 its reverse (16514453102), we get a palindrome (36649894663).

The spelling of 20135441561 in words is "twenty billion, one hundred thirty-five million, four hundred forty-one thousand, five hundred sixty-one".