261543742263371 has 2 divisors, whose sum is σ = 261543742263372. Its totient is φ = 261543742263370.

The previous prime is 261543742263361. The next prime is 261543742263379. The reversal of 261543742263371 is 173362247345162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261543742263371 - 2¹⁰ = 261543742262347 is a prime.

It is not a weakly prime, because it can be changed into another prime (261543742263379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130771871131685 + 130771871131686.

It is an arithmetic number, because the mean of its divisors is an integer number (130771871131686).

Almost surely, 2^{261543742263371} is an apocalyptic number.

261543742263371 is a deficient number, since it is larger than the sum of its proper divisors (1).

261543742263371 is an equidigital number, since it uses as much as digits as its factorization.

261543742263371 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30481920, while the sum is 56.

The spelling of 261543742263371 in words is "two hundred sixty-one trillion, five hundred forty-three billion, seven hundred forty-two million, two hundred sixty-three thousand, three hundred seventy-one".