261718322863541 has 2 divisors, whose sum is σ = 261718322863542. Its totient is φ = 261718322863540.

The previous prime is 261718322863523. The next prime is 261718322863549. The reversal of 261718322863541 is 145368223817162.

261718322863541 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., 195666130301041 + 66052192562500 = 13988071^2 + 8127250^2 .

It is a cyclic number.

It is not a de Polignac number, because 261718322863541 - 2⁴⁶ = 191349578685877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261718322863549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130859161431770 + 130859161431771.

It is an arithmetic number, because the mean of its divisors is an integer number (130859161431771).

Almost surely, 2^{261718322863541} is an apocalyptic number.

It is an amenable number.

261718322863541 is a deficient number, since it is larger than the sum of its proper divisors (1).

261718322863541 is an equidigital number, since it uses as much as digits as its factorization.

261718322863541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23224320, while the sum is 59.

The spelling of 261718322863541 in words is "two hundred sixty-one trillion, seven hundred eighteen billion, three hundred twenty-two million, eight hundred sixty-three thousand, five hundred forty-one".