261671598289 has 2 divisors, whose sum is σ = 261671598290. Its totient is φ = 261671598288.

The previous prime is 261671598263. The next prime is 261671598319. The reversal of 261671598289 is 982895176162.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 256246539264 + 5425059025 = 506208^2 + 73655^2 .

It is a cyclic number.

It is not a de Polignac number, because 261671598289 - 2⁹ = 261671597777 is a prime.

It is a super-2 number, since 2×261671598289² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261671598289.

It is not a weakly prime, because it can be changed into another prime (261671598259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130835799144 + 130835799145.

It is an arithmetic number, because the mean of its divisors is an integer number (130835799145).

Almost surely, 2^261671598289 is an apocalyptic number.

It is an amenable number.

261671598289 is a deficient number, since it is larger than the sum of its proper divisors (1).

261671598289 is an equidigital number, since it uses as much as digits as its factorization.

261671598289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 26127360, while the sum is 64.

The spelling of 261671598289 in words is "two hundred sixty-one billion, six hundred seventy-one million, five hundred ninety-eight thousand, two hundred eighty-nine".