999990 has 48 divisors (see below), whose sum is σ = 2673216. Its totient is φ = 259200.
The previous prime is 999983. The next prime is 1000003. The reversal of 999990 is 99999.
999990 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a Harshad number since it is a multiple of its sum of digits (45).
It is a nialpdrome in base 10.
It is a congruent number.
It is an unprimeable number.
999990 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3555 + ... + 3825.
It is an arithmetic number, because the mean of its divisors is an integer number (55692).
2999990 is an apocalyptic number.
999990 is a gapful number since it is divisible by the number (90) formed by its first and last digit.
It is a practical number, because each smaller number is the sum of distinct divisors of 999990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1336608).
999990 is an abundant number, since it is smaller than the sum of its proper divisors (1673226).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
999990 is a wasteful number, since it uses less digits than its factorization.
999990 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 325 (or 322 counting only the distinct ones).
The product of its (nonzero) digits is 59049, while the sum is 45.
The square root of 999990 is about 999.9949999875. The cubic root of 999990 is about 99.9996666656. Note that the first 3 decimals are identical.
999990 divided by its sum of digits (45) gives a palindrome (22222).
It can be divided in two parts, 9 and 99990, that added together give a palindrome (99999).
The spelling of 999990 in words is "nine hundred ninety-nine thousand, nine hundred ninety".
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