215987 has 4 divisors (see below), whose sum is σ = 217056. Its totient is φ = 214920.

The previous prime is 215983. The next prime is 216023. The reversal of 215987 is 789512.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 215987 - 2² = 215983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215981) 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 3 ways as a sum of consecutive naturals, for example, 128 + ... + 669.

It is an arithmetic number, because the mean of its divisors is an integer number (54264).

2²¹⁵⁹⁸⁷ is an apocalyptic number.

215987 is a deficient number, since it is larger than the sum of its proper divisors (1069).

215987 is an equidigital number, since it uses as much as digits as its factorization.

215987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1068.

The product of its digits is 5040, while the sum is 32.

The square root of 215987 is about 464.7440155613. The cubic root of 215987 is about 59.9987962721.

The spelling of 215987 in words is "two hundred fifteen thousand, nine hundred eighty-seven".