636426990191 has 2 divisors, whose sum is σ = 636426990192. Its totient is φ = 636426990190.

The previous prime is 636426990119. The next prime is 636426990203. The reversal of 636426990191 is 191099624636.

Together with previous prime (636426990119) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 636426990191 - 2¹⁰ = 636426989167 is a prime.

It is a super-4 number, since 4×636426990191⁴ (a number of 48 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636426990691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318213495095 + 318213495096.

It is an arithmetic number, because the mean of its divisors is an integer number (318213495096).

Almost surely, 2^636426990191 is an apocalyptic number.

636426990191 is a deficient number, since it is larger than the sum of its proper divisors (1).

636426990191 is an equidigital number, since it uses as much as digits as its factorization.

636426990191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3779136, while the sum is 56.

The spelling of 636426990191 in words is "six hundred thirty-six billion, four hundred twenty-six million, nine hundred ninety thousand, one hundred ninety-one".