1987109 has 4 divisors (see below), whose sum is σ = 2055660. Its totient is φ = 1918560.

The previous prime is 1987099. The next prime is 1987121. The reversal of 1987109 is 9017891.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1600225 + 386884 = 1265^2 + 622^2 .

It is a cyclic number.

It is not a de Polignac number, because 1987109 - 2¹² = 1983013 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987189) 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, 34232 + ... + 34289.

It is an arithmetic number, because the mean of its divisors is an integer number (513915).

2^1987109 is an apocalyptic number.

It is an amenable number.

1987109 is a deficient number, since it is larger than the sum of its proper divisors (68551).

1987109 is an equidigital number, since it uses as much as digits as its factorization.

1987109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68550.

The product of its (nonzero) digits is 4536, while the sum is 35.

The square root of 1987109 is about 1409.6485377568. The cubic root of 1987109 is about 125.7208272742.

The spelling of 1987109 in words is "one million, nine hundred eighty-seven thousand, one hundred nine".