188817788491 has 2 divisors, whose sum is σ = 188817788492. Its totient is φ = 188817788490.

The previous prime is 188817788473. The next prime is 188817788507. The reversal of 188817788491 is 194887718881.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 188817788491 - 2⁵ = 188817788459 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 188817788491.

It is not a weakly prime, because it can be changed into another prime (188817788791) 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, 94408894245 + 94408894246.

It is an arithmetic number, because the mean of its divisors is an integer number (94408894246).

Almost surely, 2^188817788491 is an apocalyptic number.

188817788491 is a deficient number, since it is larger than the sum of its proper divisors (1).

188817788491 is an equidigital number, since it uses as much as digits as its factorization.

188817788491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 57802752, while the sum is 70.

The spelling of 188817788491 in words is "one hundred eighty-eight billion, eight hundred seventeen million, seven hundred eighty-eight thousand, four hundred ninety-one".