999987 has 8 divisors (see below), whose sum is σ = 1339536. Its totient is φ = 663552.

The previous prime is 999983. The next prime is 1000003. The reversal of 999987 is 789999.

999987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 999987 - 2² = 999983 is a prime.

999987 is a lucky number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (999983) 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, 123 + ... + 1419.

It is an arithmetic number, because the mean of its divisors is an integer number (167442).

2⁹⁹⁹⁹⁸⁷ is an apocalyptic number.

999987 is a deficient number, since it is larger than the sum of its proper divisors (339549).

999987 is a wasteful number, since it uses less digits than its factorization.

999987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557.

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

The square root of 999987 is about 999.9934999789. The cubic root of 999987 is about 99.9995666648. Note that the first 3 decimals are identical.

The spelling of 999987 in words is "nine hundred ninety-nine thousand, nine hundred eighty-seven".