261431265021769 has 2 divisors, whose sum is σ = 261431265021770. Its totient is φ = 261431265021768.

The previous prime is 261431265021709. The next prime is 261431265021781. The reversal of 261431265021769 is 967120562134162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 235312163852544 + 26119101169225 = 15339888^2 + 5110685^2 .

It is a cyclic number.

It is not a de Polignac number, because 261431265021769 - 2¹¹ = 261431265019721 is a prime.

It is a super-2 number, since 2×261431265021769² (a number of 30 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261431265021709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130715632510884 + 130715632510885.

It is an arithmetic number, because the mean of its divisors is an integer number (130715632510885).

Almost surely, 2^{261431265021769} is an apocalyptic number.

It is an amenable number.

261431265021769 is a deficient number, since it is larger than the sum of its proper divisors (1).

261431265021769 is an equidigital number, since it uses as much as digits as its factorization.

261431265021769 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6531840, while the sum is 55.

The spelling of 261431265021769 in words is "two hundred sixty-one trillion, four hundred thirty-one billion, two hundred sixty-five million, twenty-one thousand, seven hundred sixty-nine".