987999 has 4 divisors (see below), whose sum is σ = 1317336. Its totient is φ = 658664.

The previous prime is 987997. The next prime is 988007. The reversal of 987999 is 999789.

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 987999 - 2¹ = 987997 is a prime.

It is a super-2 number, since 2×987999² = 1952284048002, which contains 22 as substring.

It is a D-number.

987999 is a modest number, since divided by 999 gives 987 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164664 + ... + 164669.

It is an arithmetic number, because the mean of its divisors is an integer number (329334).

2⁹⁸⁷⁹⁹⁹ is an apocalyptic number.

987999 is a deficient number, since it is larger than the sum of its proper divisors (329337).

987999 is a wasteful number, since it uses less digits than its factorization.

987999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329336.

The product of its digits is 367416, while the sum is 51.

The square root of 987999 is about 993.9813881557. The cubic root of 987999 is about 99.5983556445.

The spelling of 987999 in words is "nine hundred eighty-seven thousand, nine hundred ninety-nine".