1820091 has 32 divisors (see below), whose sum is σ = 3064320. Its totient is φ = 935424.

The previous prime is 1820089. The next prime is 1820111. The reversal of 1820091 is 1900281.

It is not a de Polignac number, because 1820091 - 2¹ = 1820089 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (1820051) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16051 + ... + 16163.

It is an arithmetic number, because the mean of its divisors is an integer number (95760).

2^1820091 is an apocalyptic number.

1820091 is a deficient number, since it is larger than the sum of its proper divisors (1244229).

1820091 is a wasteful number, since it uses less digits than its factorization.

1820091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 1820091 is about 1349.1074827455. The cubic root of 1820091 is about 122.0949498227.

The spelling of 1820091 in words is "one million, eight hundred twenty thousand, ninety-one".