8491761289391 has 2 divisors, whose sum is σ = 8491761289392. Its totient is φ = 8491761289390.

The previous prime is 8491761289339. The next prime is 8491761289421. The reversal of 8491761289391 is 1939821671948.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 8491761289391 - 2⁶ = 8491761289327 is a prime.

It is a super-2 number, since 2×8491761289391² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8491761289321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4245880644695 + 4245880644696.

It is an arithmetic number, because the mean of its divisors is an integer number (4245880644696).

Almost surely, 2^{8491761289391} is an apocalyptic number.

8491761289391 is a deficient number, since it is larger than the sum of its proper divisors (1).

8491761289391 is an equidigital number, since it uses as much as digits as its factorization.

8491761289391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47029248, while the sum is 68.

The spelling of 8491761289391 in words is "eight trillion, four hundred ninety-one billion, seven hundred sixty-one million, two hundred eighty-nine thousand, three hundred ninety-one".