1804991 has 2 divisors, whose sum is σ = 1804992. Its totient is φ = 1804990.

The previous prime is 1804973. The next prime is 1804993. The reversal of 1804991 is 1994081.

It is a strong prime.

It is an emirp because it is prime and its reverse (1994081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1804991 - 2⁶ = 1804927 is a prime.

Together with 1804993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1804993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 902495 + 902496.

It is an arithmetic number, because the mean of its divisors is an integer number (902496).

2^1804991 is an apocalyptic number.

1804991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1804991 is an equidigital number, since it uses as much as digits as its factorization.

1804991 is an evil number, because the sum of its binary digits is even.

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

The square root of 1804991 is about 1343.4995347971. The cubic root of 1804991 is about 121.7563667864.

The spelling of 1804991 in words is "one million, eight hundred four thousand, nine hundred ninety-one".