999940 has 36 divisors (see below), whose sum is σ = 2243556. Its totient is φ = 374272.

The previous prime is 999931. The next prime is 999953. The reversal of 999940 is 49999.

It can be written as a sum of positive squares in 6 ways, for example, as 200704 + 799236 = 448^2 + 894^2 .

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 999893 and 999902.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5694 + ... + 5866.

It is an arithmetic number, because the mean of its divisors is an integer number (62321).

2⁹⁹⁹⁹⁴⁰ 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 999940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1121778).

999940 is an abundant number, since it is smaller than the sum of its proper divisors (1243616).

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

999940 is a wasteful number, since it uses less digits than its factorization.

999940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216 (or 197 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 40.

The square root of 999940 is about 999.9699995500. The cubic root of 999940 is about 99.9979999600.

The spelling of 999940 in words is "nine hundred ninety-nine thousand, nine hundred forty".