261138758611 has 2 divisors, whose sum is σ = 261138758612. Its totient is φ = 261138758610.

The previous prime is 261138758561. The next prime is 261138758623. The reversal of 261138758611 is 116857831162.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261138758611 - 2⁷ = 261138758483 is a prime.

It is not a weakly prime, because it can be changed into another prime (261138758651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130569379305 + 130569379306.

It is an arithmetic number, because the mean of its divisors is an integer number (130569379306).

Almost surely, 2^261138758611 is an apocalyptic number.

261138758611 is a deficient number, since it is larger than the sum of its proper divisors (1).

261138758611 is an equidigital number, since it uses as much as digits as its factorization.

261138758611 is an evil number, because the sum of its binary digits is even.

The product of its digits is 483840, while the sum is 49.

The spelling of 261138758611 in words is "two hundred sixty-one billion, one hundred thirty-eight million, seven hundred fifty-eight thousand, six hundred eleven".