987817 has 4 divisors (see below), whose sum is σ = 990036. Its totient is φ = 985600.

The previous prime is 987809. The next prime is 987821. The reversal of 987817 is 718789.

987817 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 718789 = 19 ⋅37831.

It can be written as a sum of positive squares in 2 ways, for example, as 553536 + 434281 = 744^2 + 659^2 .

It is a cyclic number.

It is not a de Polignac number, because 987817 - 2³ = 987809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 987817.

It is not an unprimeable number, because it can be changed into a prime (981817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 184 + ... + 1417.

It is an arithmetic number, because the mean of its divisors is an integer number (247509).

2⁹⁸⁷⁸¹⁷ is an apocalyptic number.

It is an amenable number.

987817 is a deficient number, since it is larger than the sum of its proper divisors (2219).

987817 is a wasteful number, since it uses less digits than its factorization.

987817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2218.

The product of its digits is 28224, while the sum is 40.

The square root of 987817 is about 993.8898329292. The cubic root of 987817 is about 99.5922395743.

The spelling of 987817 in words is "nine hundred eighty-seven thousand, eight hundred seventeen".