201865245661 has 2 divisors, whose sum is σ = 201865245662. Its totient is φ = 201865245660.

The previous prime is 201865245641. The next prime is 201865245677. The reversal of 201865245661 is 166542568102.

201865245661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 139282718436 + 62582527225 = 373206^2 + 250165^2 .

It is a cyclic number.

It is not a de Polignac number, because 201865245661 - 2¹⁷ = 201865114589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201865245641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100932622830 + 100932622831.

It is an arithmetic number, because the mean of its divisors is an integer number (100932622831).

Almost surely, 2^201865245661 is an apocalyptic number.

It is an amenable number.

201865245661 is a deficient number, since it is larger than the sum of its proper divisors (1).

201865245661 is an equidigital number, since it uses as much as digits as its factorization.

201865245661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 691200, while the sum is 46.

The spelling of 201865245661 in words is "two hundred one billion, eight hundred sixty-five million, two hundred forty-five thousand, six hundred sixty-one".