66798191 has 2 divisors, whose sum is σ = 66798192. Its totient is φ = 66798190.

The previous prime is 66798181. The next prime is 66798197. The reversal of 66798191 is 19189766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66798191 - 2²² = 62603887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66798197) 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, 33399095 + 33399096.

It is an arithmetic number, because the mean of its divisors is an integer number (33399096).

Almost surely, 2^66798191 is an apocalyptic number.

66798191 is a deficient number, since it is larger than the sum of its proper divisors (1).

66798191 is an equidigital number, since it uses as much as digits as its factorization.

66798191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 47.

The square root of 66798191 is about 8173.0160283704. The cubic root of 66798191 is about 405.7466103946.

The spelling of 66798191 in words is "sixty-six million, seven hundred ninety-eight thousand, one hundred ninety-one".