999634688 has 72 divisors (see below), whose sum is σ = 2262094800. Its totient is φ = 437059584.

The previous prime is 999634687. The next prime is 999634703. The reversal of 999634688 is 886436999.

It is a Cunningham number, because it is equal to 31617²-1.

It is a super-3 number, since 3×999634688³ (a number of 28 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 999634688.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999634687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55328 + ... + 71136.

Almost surely, 2^999634688 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 999634688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1131047400).

999634688 is an abundant number, since it is smaller than the sum of its proper divisors (1262460112).

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

999634688 is a wasteful number, since it uses less digits than its factorization.

999634688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15857 (or 15843 counting only the distinct ones).

The product of its digits is 20155392, while the sum is 62.

The square root of 999634688 is about 31616.9999841857. Note that the first 4 decimals coincide. The cubic root of 999634688 is about 999.8782145022.

The spelling of 999634688 in words is "nine hundred ninety-nine million, six hundred thirty-four thousand, six hundred eighty-eight".