8161291993691 has 2 divisors, whose sum is σ = 8161291993692. Its totient is φ = 8161291993690.

The previous prime is 8161291993667. The next prime is 8161291993721. The reversal of 8161291993691 is 1963991921618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8161291993691 - 2⁶ = 8161291993627 is a prime.

It is not a weakly prime, because it can be changed into another prime (8161291993601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4080645996845 + 4080645996846.

It is an arithmetic number, because the mean of its divisors is an integer number (4080645996846).

Almost surely, 2^{8161291993691} is an apocalyptic number.

8161291993691 is a deficient number, since it is larger than the sum of its proper divisors (1).

8161291993691 is an equidigital number, since it uses as much as digits as its factorization.

8161291993691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11337408, while the sum is 65.

The spelling of 8161291993691 in words is "eight trillion, one hundred sixty-one billion, two hundred ninety-one million, nine hundred ninety-three thousand, six hundred ninety-one".