199960660891 has 2 divisors, whose sum is σ = 199960660892. Its totient is φ = 199960660890.

The previous prime is 199960660873. The next prime is 199960660901. The reversal of 199960660891 is 198066069991.

It is a strong prime.

It is an emirp because it is prime and its reverse (198066069991) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 168099096661 and 166690990861.

It is a cyclic number.

It is not a de Polignac number, because 199960660891 - 2⁵ = 199960660859 is a prime.

It is not a weakly prime, because it can be changed into another prime (199960660811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99980330445 + 99980330446.

It is an arithmetic number, because the mean of its divisors is an integer number (99980330446).

Almost surely, 2^199960660891 is an apocalyptic number.

199960660891 is a deficient number, since it is larger than the sum of its proper divisors (1).

199960660891 is an equidigital number, since it uses as much as digits as its factorization.

199960660891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11337408, while the sum is 64.

The spelling of 199960660891 in words is "one hundred ninety-nine billion, nine hundred sixty million, six hundred sixty thousand, eight hundred ninety-one".