978888191 has 2 divisors, whose sum is σ = 978888192. Its totient is φ = 978888190.

The previous prime is 978888173. The next prime is 978888193. The reversal of 978888191 is 191888879.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 978888191 - 2²² = 974693887 is a prime.

It is a Sophie Germain prime.

Together with 978888193, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 978888191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (978888193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 489444095 + 489444096.

It is an arithmetic number, because the mean of its divisors is an integer number (489444096).

Almost surely, 2^978888191 is an apocalyptic number.

978888191 is a deficient number, since it is larger than the sum of its proper divisors (1).

978888191 is an equidigital number, since it uses as much as digits as its factorization.

978888191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2322432, while the sum is 59.

The square root of 978888191 is about 31287.1889277385. The cubic root of 978888191 is about 992.9126180187.

It can be divided in two parts, 9788 and 88191, that added together give a palindrome (97979).

The spelling of 978888191 in words is "nine hundred seventy-eight million, eight hundred eighty-eight thousand, one hundred ninety-one".