998778 has 32 divisors (see below), whose sum is σ = 2243520. Its totient is φ = 293760.

The previous prime is 998759. The next prime is 998779. The reversal of 998778 is 877899.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (998779) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2238 + ... + 2646.

It is an arithmetic number, because the mean of its divisors is an integer number (70110).

2⁹⁹⁸⁷⁷⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 998778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1121760).

998778 is an abundant number, since it is smaller than the sum of its proper divisors (1244742).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

998778 is a wasteful number, since it uses less digits than its factorization.

998778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 462.

The product of its digits is 254016, while the sum is 48.

The square root of 998778 is about 999.3888132254. The cubic root of 998778 is about 99.9592500633.

The spelling of 998778 in words is "nine hundred ninety-eight thousand, seven hundred seventy-eight".