168404037491 has 2 divisors, whose sum is σ = 168404037492. Its totient is φ = 168404037490.

The previous prime is 168404037401. The next prime is 168404037493. The reversal of 168404037491 is 194730404861.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-168404037491 is a prime.

Together with 168404037493, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (168404037493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84202018745 + 84202018746.

It is an arithmetic number, because the mean of its divisors is an integer number (84202018746).

Almost surely, 2^168404037491 is an apocalyptic number.

168404037491 is a deficient number, since it is larger than the sum of its proper divisors (1).

168404037491 is an equidigital number, since it uses as much as digits as its factorization.

168404037491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 580608, while the sum is 47.

The spelling of 168404037491 in words is "one hundred sixty-eight billion, four hundred four million, thirty-seven thousand, four hundred ninety-one".