991404000 has 144 divisors (see below), whose sum is σ = 3518620560. Its totient is φ = 264364800.

The previous prime is 991403993. The next prime is 991404013. The reversal of 991404000 is 404199.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22231 + ... + 49769.

It is an arithmetic number, because the mean of its divisors is an integer number (24434865).

Almost surely, 2^991404000 is an apocalyptic number.

991404000 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 991404000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1759310280).

991404000 is an abundant number, since it is smaller than the sum of its proper divisors (2527216560).

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

991404000 is a wasteful number, since it uses less digits than its factorization.

991404000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27570 (or 27549 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 991404000 is about 31486.5685650247. The cubic root of 991404000 is about 997.1264170975.

Adding to 991404000 its reverse (404199), we get a palindrome (991808199).

The spelling of 991404000 in words is "nine hundred ninety-one million, four hundred four thousand".