999998784 has 140 divisors (see below), whose sum is σ = 3093561504. Its totient is φ = 318802176.

The previous prime is 999998777. The next prime is 999998789. The reversal of 999998784 is 487899999.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999998789) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 115039 + ... + 123425.

Almost surely, 2^999998784 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999998784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1546780752).

999998784 is an abundant number, since it is smaller than the sum of its proper divisors (2093562720).

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

999998784 is a wasteful number, since it uses less digits than its factorization.

999998784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8434 (or 8415 counting only the distinct ones).

The product of its digits is 105815808, while the sum is 72.

The square root of 999998784 is about 31622.7573750298. The cubic root of 999998784 is about 999.9995946665. Note that the first 3 decimals are identical.

The spelling of 999998784 in words is "nine hundred ninety-nine million, nine hundred ninety-eight thousand, seven hundred eighty-four".