1919608891 has 2 divisors, whose sum is σ = 1919608892. Its totient is φ = 1919608890.

The previous prime is 1919608879. The next prime is 1919608897. The reversal of 1919608891 is 1988069191.

It is a strong prime.

It is an emirp because it is prime and its reverse (1988069191) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1688096161 and 1616908861.

It is a cyclic number.

It is not a de Polignac number, because 1919608891 - 2⁷ = 1919608763 is a prime.

It is not a weakly prime, because it can be changed into another prime (1919608897) 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, 959804445 + 959804446.

It is an arithmetic number, because the mean of its divisors is an integer number (959804446).

Almost surely, 2^1919608891 is an apocalyptic number.

1919608891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1919608891 is an equidigital number, since it uses as much as digits as its factorization.

1919608891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 279936, while the sum is 52.

The square root of 1919608891 is about 43813.3414726610. The cubic root of 1919608891 is about 1242.8086031367.

The spelling of 1919608891 in words is "one billion, nine hundred nineteen million, six hundred eight thousand, eight hundred ninety-one".