1189855866 has 8 divisors (see below), whose sum is σ = 2379711744. Its totient is φ = 396618620.

The previous prime is 1189855861. The next prime is 1189855871. The reversal of 1189855866 is 6685589811.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1189855861) and next prime (1189855871).

It is a sphenic number, since it is the product of 3 distinct primes.

1189855866 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (1189855861) 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 in 3 ways as a sum of consecutive naturals, for example, 99154650 + ... + 99154661.

It is an arithmetic number, because the mean of its divisors is an integer number (297463968).

Almost surely, 2^1189855866 is an apocalyptic number.

1189855866 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1189855866 is a wasteful number, since it uses less digits than its factorization.

1189855866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198309316.

The product of its digits is 4147200, while the sum is 57.

The square root of 1189855866 is about 34494.2874400965. The cubic root of 1189855866 is about 1059.6557164803.

The spelling of 1189855866 in words is "one billion, one hundred eighty-nine million, eight hundred fifty-five thousand, eight hundred sixty-six".