1991304 has 80 divisors (see below), whose sum is σ = 6388800. Its totient is φ = 567648.

The previous prime is 1991293. The next prime is 1991351. The reversal of 1991304 is 4031991.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4317 + ... + 4755.

It is an arithmetic number, because the mean of its divisors is an integer number (79860).

2^1991304 is an apocalyptic number.

1991304 is a gapful number since it is divisible by the number (14) 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 1991304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3194400).

1991304 is an abundant number, since it is smaller than the sum of its proper divisors (4397496).

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

1991304 is a wasteful number, since it uses less digits than its factorization.

1991304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464 (or 451 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 1991304 is about 1411.1357128214. The cubic root of 1991304 is about 125.8092351360.

The spelling of 1991304 in words is "one million, nine hundred ninety-one thousand, three hundred four".