1991841 has 8 divisors (see below), whose sum is σ = 2673984. Its totient is φ = 1318800.

The previous prime is 1991837. The next prime is 1991849. The reversal of 1991841 is 1481991.

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

It is not a de Polignac number, because 1991841 - 2² = 1991837 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1746 + ... + 2651.

It is an arithmetic number, because the mean of its divisors is an integer number (334248).

2^1991841 is an apocalyptic number.

It is an amenable number.

1991841 is a deficient number, since it is larger than the sum of its proper divisors (682143).

1991841 is a wasteful number, since it uses less digits than its factorization.

1991841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4551.

The product of its digits is 2592, while the sum is 33.

The square root of 1991841 is about 1411.3259722686. The cubic root of 1991841 is about 125.8205432180.

The spelling of 1991841 in words is "one million, nine hundred ninety-one thousand, eight hundred forty-one".