1987111 has 4 divisors (see below), whose sum is σ = 2270992. Its totient is φ = 1703232.

The previous prime is 1987099. The next prime is 1987121. The reversal of 1987111 is 1117891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1117891 = 31 ⋅36061.

It is a cyclic number.

It is not a de Polignac number, because 1987111 - 2¹⁵ = 1954343 is a prime.

It is a super-2 number, since 2×1987111² = 7897220252642, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1987111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141930 + ... + 141943.

It is an arithmetic number, because the mean of its divisors is an integer number (567748).

2^1987111 is an apocalyptic number.

1987111 is a deficient number, since it is larger than the sum of its proper divisors (283881).

1987111 is an equidigital number, since it uses as much as digits as its factorization.

1987111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283880.

The product of its digits is 504, while the sum is 28.

The square root of 1987111 is about 1409.6492471533. The cubic root of 1987111 is about 125.7208694530.

The spelling of 1987111 in words is "one million, nine hundred eighty-seven thousand, one hundred eleven".