999539840 has 128 divisors (see below), whose sum is σ = 2709201600. Its totient is φ = 349581312.

The previous prime is 999539833. The next prime is 999539873. The reversal of 999539840 is 48935999.

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 154919 + ... + 161241.

Almost surely, 2^999539840 is an apocalyptic number.

It is a pronic number, being equal to 31615×31616.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999539840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1354600800).

999539840 is an abundant number, since it is smaller than the sum of its proper divisors (1709661760).

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

999539840 is a wasteful number, since it uses less digits than its factorization.

999539840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6374 (or 6362 counting only the distinct ones).

The product of its (nonzero) digits is 3149280, while the sum is 56.

The square root of 999539840 is about 31615.4999960462. The cubic root of 999539840 is about 999.8465897998.

The spelling of 999539840 in words is "nine hundred ninety-nine million, five hundred thirty-nine thousand, eight hundred forty".