999999648 has 96 divisors (see below), whose sum is σ = 2922494400. Its totient is φ = 332667648.

The previous prime is 999999613. The next prime is 999999667. The reversal of 999999648 is 846999999.

It is a tau number, because it is divible by the number of its divisors (96).

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

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 632523 + ... + 634101.

It is an arithmetic number, because the mean of its divisors is an integer number (30442650).

Almost surely, 2^999999648 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 999999648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1461247200).

999999648 is an abundant number, since it is smaller than the sum of its proper divisors (1922494752).

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

999999648 is a wasteful number, since it uses less digits than its factorization.

999999648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2331 (or 2317 counting only the distinct ones).

The product of its digits is 102036672, while the sum is 72.

The square root of 999999648 is about 31622.7710360746. The cubic root of 999999648 is about 999.9998826667. Note that the first 3 decimals are identical.

The spelling of 999999648 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, six hundred forty-eight".