39987 has 8 divisors (see below), whose sum is σ = 59280. Its totient is φ = 26640.

The previous prime is 39983. The next prime is 39989. The reversal of 39987 is 78993.

39987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 39987 - 2² = 39983 is a prime.

39987 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 39987.

It is not an unprimeable number, because it can be changed into a prime (39983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 714 + ... + 767.

It is an arithmetic number, because the mean of its divisors is an integer number (7410).

2³⁹⁹⁸⁷ is an apocalyptic number.

39987 is a deficient number, since it is larger than the sum of its proper divisors (19293).

39987 is a wasteful number, since it uses less digits than its factorization.

39987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1490 (or 1484 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 39987 is about 199.9674973589. The cubic root of 39987 is about 34.1958135842.

It can be divided in two parts, 3998 and 7, that added together give a triangular number (4005 = T₈₉).

The spelling of 39987 in words is "thirty-nine thousand, nine hundred eighty-seven".