1991445 has 8 divisors (see below), whose sum is σ = 3186336. Its totient is φ = 1062096.

The previous prime is 1991443. The next prime is 1991449. The reversal of 1991445 is 5441991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1991445 - 2¹ = 1991443 is a prime.

It is a super-3 number, since 3×1991445³ = 23693335506079338375, which contains 333 as substring.

1991445 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66367 + ... + 66396.

It is an arithmetic number, because the mean of its divisors is an integer number (398292).

2^1991445 is an apocalyptic number.

1991445 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1991445 is a deficient number, since it is larger than the sum of its proper divisors (1194891).

1991445 is a wasteful number, since it uses less digits than its factorization.

1991445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132771.

The product of its digits is 6480, while the sum is 33.

The square root of 1991445 is about 1411.1856716960. The cubic root of 1991445 is about 125.8122044940.

The spelling of 1991445 in words is "one million, nine hundred ninety-one thousand, four hundred forty-five".