1987749 has 6 divisors (see below), whose sum is σ = 2871206. Its totient is φ = 1325160.

The previous prime is 1987709. The next prime is 1987789. The reversal of 1987749 is 9477891.

It is an interprime number because it is at equal distance from previous prime (1987709) and next prime (1987789).

It can be written as a sum of positive squares in only one way, i.e., 1979649 + 8100 = 1407^2 + 90^2 .

It is not a de Polignac number, because 1987749 - 2⁷ = 1987621 is a prime.

It is a super-2 number, since 2×1987749² = 7902292174002, which contains 22 as substring.

It is a Duffinian number.

1987749 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987709) 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 5 ways as a sum of consecutive naturals, for example, 110422 + ... + 110439.

2^1987749 is an apocalyptic number.

It is an amenable number.

1987749 is a deficient number, since it is larger than the sum of its proper divisors (883457).

1987749 is a wasteful number, since it uses less digits than its factorization.

1987749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220867 (or 220864 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 1987749 is about 1409.8755264207. The cubic root of 1987749 is about 125.7343230433.

The spelling of 1987749 in words is "one million, nine hundred eighty-seven thousand, seven hundred forty-nine".