259781861 has 2 divisors, whose sum is σ = 259781862. Its totient is φ = 259781860.

The previous prime is 259781827. The next prime is 259781867. The reversal of 259781861 is 168187952.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 256992961 + 2788900 = 16031^2 + 1670^2 .

It is a cyclic number.

It is not a de Polignac number, because 259781861 - 2²² = 255587557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (259781867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 129890930 + 129890931.

It is an arithmetic number, because the mean of its divisors is an integer number (129890931).

Almost surely, 2^259781861 is an apocalyptic number.

It is an amenable number.

259781861 is a deficient number, since it is larger than the sum of its proper divisors (1).

259781861 is an equidigital number, since it uses as much as digits as its factorization.

259781861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 241920, while the sum is 47.

The square root of 259781861 is about 16117.7498739743. The cubic root of 259781861 is about 638.0718833914.

The spelling of 259781861 in words is "two hundred fifty-nine million, seven hundred eighty-one thousand, eight hundred sixty-one".