261005761091 has 2 divisors, whose sum is σ = 261005761092. Its totient is φ = 261005761090.

The previous prime is 261005761073. The next prime is 261005761147. The reversal of 261005761091 is 190167500162.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261005761091 is a prime.

It is not a weakly prime, because it can be changed into another prime (261005761591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130502880545 + 130502880546.

It is an arithmetic number, because the mean of its divisors is an integer number (130502880546).

Almost surely, 2^261005761091 is an apocalyptic number.

261005761091 is a deficient number, since it is larger than the sum of its proper divisors (1).

261005761091 is an equidigital number, since it uses as much as digits as its factorization.

261005761091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 38.

The spelling of 261005761091 in words is "two hundred sixty-one billion, five million, seven hundred sixty-one thousand, ninety-one".