261539484887377 has 2 divisors, whose sum is σ = 261539484887378. Its totient is φ = 261539484887376.

The previous prime is 261539484887311. The next prime is 261539484887531. The reversal of 261539484887377 is 773788484935162.

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., 260433462478401 + 1106022408976 = 16137951^2 + 1051676^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261539484887377 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261539484887377.

It is not a weakly prime, because it can be changed into another prime (261539484887777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130769742443688 + 130769742443689.

It is an arithmetic number, because the mean of its divisors is an integer number (130769742443689).

Almost surely, 2^{261539484887377} is an apocalyptic number.

It is an amenable number.

261539484887377 is a deficient number, since it is larger than the sum of its proper divisors (1).

261539484887377 is an equidigital number, since it uses as much as digits as its factorization.

261539484887377 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13655900160, while the sum is 82.

The spelling of 261539484887377 in words is "two hundred sixty-one trillion, five hundred thirty-nine billion, four hundred eighty-four million, eight hundred eighty-seven thousand, three hundred seventy-seven".