261710561251 has 2 divisors, whose sum is σ = 261710561252. Its totient is φ = 261710561250.

The previous prime is 261710561069. The next prime is 261710561257. The reversal of 261710561251 is 152165017162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261710561251 - 2¹¹ = 261710559203 is a prime.

It is a super-6 number, since 6×261710561251⁶ (a number of 70 digits) contains 666666 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261710561251.

It is not a weakly prime, because it can be changed into another prime (261710561257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130855280625 + 130855280626.

It is an arithmetic number, because the mean of its divisors is an integer number (130855280626).

Almost surely, 2^261710561251 is an apocalyptic number.

261710561251 is a deficient number, since it is larger than the sum of its proper divisors (1).

261710561251 is an equidigital number, since it uses as much as digits as its factorization.

261710561251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 37.

The spelling of 261710561251 in words is "two hundred sixty-one billion, seven hundred ten million, five hundred sixty-one thousand, two hundred fifty-one".