205102061542661 has 2 divisors, whose sum is σ = 205102061542662. Its totient is φ = 205102061542660.

The previous prime is 205102061542633. The next prime is 205102061542663. The reversal of 205102061542661 is 166245160201502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148713000702436 + 56389060840225 = 12194794^2 + 7509265^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205102061542661 is a prime.

Together with 205102061542663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205102061542663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102551030771330 + 102551030771331.

It is an arithmetic number, because the mean of its divisors is an integer number (102551030771331).

Almost surely, 2^{205102061542661} is an apocalyptic number.

It is an amenable number.

205102061542661 is a deficient number, since it is larger than the sum of its proper divisors (1).

205102061542661 is an equidigital number, since it uses as much as digits as its factorization.

205102061542661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 172800, while the sum is 41.

The spelling of 205102061542661 in words is "two hundred five trillion, one hundred two billion, sixty-one million, five hundred forty-two thousand, six hundred sixty-one".