1165987 has 4 divisors (see below), whose sum is σ = 1175296. Its totient is φ = 1156680.

The previous prime is 1165951. The next prime is 1165991. The reversal of 1165987 is 7895611.

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 1165987 - 2¹⁵ = 1133219 is a prime.

It is a Duffinian number.

1165987 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1165937) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4464 + ... + 4717.

It is an arithmetic number, because the mean of its divisors is an integer number (293824).

2^1165987 is an apocalyptic number.

1165987 is a deficient number, since it is larger than the sum of its proper divisors (9309).

1165987 is an equidigital number, since it uses as much as digits as its factorization.

1165987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9308.

The product of its digits is 15120, while the sum is 37.

The square root of 1165987 is about 1079.8087793679. The cubic root of 1165987 is about 105.2522130419.

The spelling of 1165987 in words is "one million, one hundred sixty-five thousand, nine hundred eighty-seven".