1189891 has 2 divisors, whose sum is σ = 1189892. Its totient is φ = 1189890.

The previous prime is 1189879. The next prime is 1189897. The reversal of 1189891 is 1989811.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (1989811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1189891 - 2⁷ = 1189763 is a prime.

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 1189891.

It is not a weakly prime, because it can be changed into another prime (1189897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 594945 + 594946.

It is an arithmetic number, because the mean of its divisors is an integer number (594946).

2^1189891 is an apocalyptic number.

1189891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1189891 is an equidigital number, since it uses as much as digits as its factorization.

1189891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 37.

The square root of 1189891 is about 1090.8212502514. The cubic root of 1189891 is about 105.9666146197.

It can be divided in two parts, 1189 and 891, that added together give a triangular number (2080 = T₆₄).

The spelling of 1189891 in words is "one million, one hundred eighty-nine thousand, eight hundred ninety-one".