1291541967581 has 2 divisors, whose sum is σ = 1291541967582. Its totient is φ = 1291541967580.

The previous prime is 1291541967523. The next prime is 1291541967587. The reversal of 1291541967581 is 1857691451921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1279624752025 + 11917215556 = 1131205^2 + 109166^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291541967581 - 2⁶ = 1291541967517 is a prime.

It is a super-2 number, since 2×1291541967581² (a number of 25 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 1291541967581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291541967587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645770983790 + 645770983791.

It is an arithmetic number, because the mean of its divisors is an integer number (645770983791).

Almost surely, 2^{1291541967581} is an apocalyptic number.

It is an amenable number.

1291541967581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291541967581 is an equidigital number, since it uses as much as digits as its factorization.

1291541967581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5443200, while the sum is 59.

The spelling of 1291541967581 in words is "one trillion, two hundred ninety-one billion, five hundred forty-one million, nine hundred sixty-seven thousand, five hundred eighty-one".