1191218489 has 2 divisors, whose sum is σ = 1191218490. Its totient is φ = 1191218488.

The previous prime is 1191218477. The next prime is 1191218519. The reversal of 1191218489 is 9848121911.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1095080464 + 96138025 = 33092^2 + 9805^2 .

It is a cyclic number.

It is not a de Polignac number, because 1191218489 - 2⁸ = 1191218233 is a prime.

It is not a weakly prime, because it can be changed into another prime (1191218429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 595609244 + 595609245.

It is an arithmetic number, because the mean of its divisors is an integer number (595609245).

Almost surely, 2^1191218489 is an apocalyptic number.

It is an amenable number.

1191218489 is a deficient number, since it is larger than the sum of its proper divisors (1).

1191218489 is an equidigital number, since it uses as much as digits as its factorization.

1191218489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 44.

The square root of 1191218489 is about 34514.0332183881. The cubic root of 1191218489 is about 1060.0600680924.

The spelling of 1191218489 in words is "one billion, one hundred ninety-one million, two hundred eighteen thousand, four hundred eighty-nine".