661362098261 has 2 divisors, whose sum is σ = 661362098262. Its totient is φ = 661362098260.

The previous prime is 661362098153. The next prime is 661362098339. The reversal of 661362098261 is 162890263166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 367266300625 + 294095797636 = 606025^2 + 542306^2 .

It is a cyclic number.

It is not a de Polignac number, because 661362098261 - 2³⁰ = 660288356437 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661362068261) 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, 330681049130 + 330681049131.

It is an arithmetic number, because the mean of its divisors is an integer number (330681049131).

Almost surely, 2^661362098261 is an apocalyptic number.

It is an amenable number.

661362098261 is a deficient number, since it is larger than the sum of its proper divisors (1).

661362098261 is an equidigital number, since it uses as much as digits as its factorization.

661362098261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1119744, while the sum is 50.

The spelling of 661362098261 in words is "six hundred sixty-one billion, three hundred sixty-two million, ninety-eight thousand, two hundred sixty-one".