1840991 has 4 divisors (see below), whose sum is σ = 1845984. Its totient is φ = 1836000.

The previous prime is 1840973. The next prime is 1841003. The reversal of 1840991 is 1990481.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1840991 - 2¹⁰ = 1839967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1840921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1895 + ... + 2696.

It is an arithmetic number, because the mean of its divisors is an integer number (461496).

2^1840991 is an apocalyptic number.

1840991 is a deficient number, since it is larger than the sum of its proper divisors (4993).

1840991 is an equidigital number, since it uses as much as digits as its factorization.

1840991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4992.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 1840991 is about 1356.8312348999. The cubic root of 1840991 is about 122.5605087713.

The spelling of 1840991 in words is "one million, eight hundred forty thousand, nine hundred ninety-one".