66557422091 has 2 divisors, whose sum is σ = 66557422092. Its totient is φ = 66557422090.

The previous prime is 66557422079. The next prime is 66557422093. The reversal of 66557422091 is 19022475566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66557422091 - 2³⁰ = 65483680267 is a prime.

Together with 66557422093, 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 (66557422093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33278711045 + 33278711046.

It is an arithmetic number, because the mean of its divisors is an integer number (33278711046).

Almost surely, 2^66557422091 is an apocalyptic number.

66557422091 is a deficient number, since it is larger than the sum of its proper divisors (1).

66557422091 is an equidigital number, since it uses as much as digits as its factorization.

66557422091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 907200, while the sum is 47.

The spelling of 66557422091 in words is "sixty-six billion, five hundred fifty-seven million, four hundred twenty-two thousand, ninety-one".