20203143661 has 2 divisors, whose sum is σ = 20203143662. Its totient is φ = 20203143660.

The previous prime is 20203143659. The next prime is 20203143733. The reversal of 20203143661 is 16634130202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17309349225 + 2893794436 = 131565^2 + 53794^2 .

It is a cyclic number.

It is not a de Polignac number, because 20203143661 - 2¹ = 20203143659 is a prime.

Together with 20203143659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20203149661) 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, 10101571830 + 10101571831.

It is an arithmetic number, because the mean of its divisors is an integer number (10101571831).

Almost surely, 2^20203143661 is an apocalyptic number.

It is an amenable number.

20203143661 is a deficient number, since it is larger than the sum of its proper divisors (1).

20203143661 is an equidigital number, since it uses as much as digits as its factorization.

20203143661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 28.

Adding to 20203143661 its reverse (16634130202), we get a palindrome (36837273863).

The spelling of 20203143661 in words is "twenty billion, two hundred three million, one hundred forty-three thousand, six hundred sixty-one".