999780 has 48 divisors (see below), whose sum is σ = 2950080. Its totient is φ = 252288.

The previous prime is 999773. The next prime is 999809. The reversal of 999780 is 87999.

It is a happy number.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

999780 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 15 ways as a sum of consecutive naturals, for example, 702 + ... + 1578.

It is an arithmetic number, because the mean of its divisors is an integer number (61460).

2⁹⁹⁹⁷⁸⁰ 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 999780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1475040).

999780 is an abundant number, since it is smaller than the sum of its proper divisors (1950300).

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

999780 is a wasteful number, since it uses less digits than its factorization.

999780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 908 (or 906 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 42.

The square root of 999780 is about 999.8899939493. The cubic root of 999780 is about 99.9926661288.

The spelling of 999780 in words is "nine hundred ninety-nine thousand, seven hundred eighty".