261705761 has 2 divisors, whose sum is σ = 261705762. Its totient is φ = 261705760.

The previous prime is 261705737. The next prime is 261705767. The reversal of 261705761 is 167507162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 255360400 + 6345361 = 15980^2 + 2519^2 .

It is a cyclic number.

It is not a de Polignac number, because 261705761 - 2¹⁸ = 261443617 is a prime.

It is not a weakly prime, because it can be changed into another prime (261705767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130852880 + 130852881.

It is an arithmetic number, because the mean of its divisors is an integer number (130852881).

Almost surely, 2^261705761 is an apocalyptic number.

It is an amenable number.

261705761 is a deficient number, since it is larger than the sum of its proper divisors (1).

261705761 is an equidigital number, since it uses as much as digits as its factorization.

261705761 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 261705761 is about 16177.3224298708. The cubic root of 261705761 is about 639.6431612666.

The spelling of 261705761 in words is "two hundred sixty-one million, seven hundred five thousand, seven hundred sixty-one".