1185491987 has 4 divisors (see below), whose sum is σ = 1223733696. Its totient is φ = 1147250280.

The previous prime is 1185491977. The next prime is 1185492019. The reversal of 1185491987 is 7891945811.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1185491987 - 2⁴ = 1185491971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1185491977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19120808 + ... + 19120869.

It is an arithmetic number, because the mean of its divisors is an integer number (305933424).

Almost surely, 2^1185491987 is an apocalyptic number.

1185491987 is a deficient number, since it is larger than the sum of its proper divisors (38241709).

1185491987 is an equidigital number, since it uses as much as digits as its factorization.

1185491987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38241708.

The product of its digits is 725760, while the sum is 53.

The square root of 1185491987 is about 34430.9742383221. The cubic root of 1185491987 is about 1058.3586758861.

The spelling of 1185491987 in words is "one billion, one hundred eighty-five million, four hundred ninety-one thousand, nine hundred eighty-seven".