197788664791 has 2 divisors, whose sum is σ = 197788664792. Its totient is φ = 197788664790.

The previous prime is 197788664789. The next prime is 197788664803. The reversal of 197788664791 is 197466887791.

It is a weak prime.

It is an emirp because it is prime and its reverse (197466887791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 197788664791 - 2¹ = 197788664789 is a prime.

Together with 197788664789, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (197788664191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98894332395 + 98894332396.

It is an arithmetic number, because the mean of its divisors is an integer number (98894332396).

Almost surely, 2^197788664791 is an apocalyptic number.

197788664791 is a deficient number, since it is larger than the sum of its proper divisors (1).

197788664791 is an equidigital number, since it uses as much as digits as its factorization.

197788664791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 256048128, while the sum is 73.

The spelling of 197788664791 in words is "one hundred ninety-seven billion, seven hundred eighty-eight million, six hundred sixty-four thousand, seven hundred ninety-one".