261260398409 has 2 divisors, whose sum is σ = 261260398410. Its totient is φ = 261260398408.

The previous prime is 261260398247. The next prime is 261260398423. The reversal of 261260398409 is 904893062162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 252936573184 + 8323825225 = 502928^2 + 91235^2 .

It is a cyclic number.

It is not a de Polignac number, because 261260398409 - 2³² = 256965431113 is a prime.

It is not a weakly prime, because it can be changed into another prime (261260398439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130630199204 + 130630199205.

It is an arithmetic number, because the mean of its divisors is an integer number (130630199205).

Almost surely, 2^261260398409 is an apocalyptic number.

It is an amenable number.

261260398409 is a deficient number, since it is larger than the sum of its proper divisors (1).

261260398409 is an equidigital number, since it uses as much as digits as its factorization.

261260398409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1119744, while the sum is 50.

The spelling of 261260398409 in words is "two hundred sixty-one billion, two hundred sixty million, three hundred ninety-eight thousand, four hundred nine".