999540 has 60 divisors (see below), whose sum is σ = 3140676. Its totient is φ = 266112.

The previous prime is 999529. The next prime is 999541. The reversal of 999540 is 45999.

It can be written as a sum of positive squares in 2 ways, for example, as 156816 + 842724 = 396^2 + 918^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 999495 and 999504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999541) 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, 1312 + ... + 1928.

2⁹⁹⁹⁵⁴⁰ is an apocalyptic number.

999540 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1570338).

999540 is an abundant number, since it is smaller than the sum of its proper divisors (2141136).

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

999540 is a wasteful number, since it uses less digits than its factorization.

999540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 638 (or 627 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 999540 is about 999.7699735439. The cubic root of 999540 is about 99.9846643150.

The spelling of 999540 in words is "nine hundred ninety-nine thousand, five hundred forty".