9998987 has 4 divisors (see below), whose sum is σ = 10006800. Its totient is φ = 9991176.

The previous prime is 9998977. The next prime is 9999047. The reversal of 9998987 is 7898999.

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, and also an emirpimes, since its reverse is a distinct semiprime: 7898999 = 17 ⋅464647.

It is a cyclic number.

It is not a de Polignac number, because 9998987 - 2⁴ = 9998971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9998977) 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, 1487 + ... + 4712.

It is an arithmetic number, because the mean of its divisors is an integer number (2501700).

Almost surely, 2^9998987 is an apocalyptic number.

9998987 is a deficient number, since it is larger than the sum of its proper divisors (7813).

9998987 is a wasteful number, since it uses less digits than its factorization.

9998987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7812.

The product of its digits is 2939328, while the sum is 59.

The square root of 9998987 is about 3162.1174867484. The cubic root of 9998987 is about 215.4361939497.

The spelling of 9998987 in words is "nine million, nine hundred ninety-eight thousand, nine hundred eighty-seven".