1820385 has 24 divisors (see below), whose sum is σ = 3606720. Its totient is φ = 832032.

The previous prime is 1820353. The next prime is 1820387. The reversal of 1820385 is 5830281.

It is a happy number.

It is not a de Polignac number, because 1820385 - 2⁵ = 1820353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1820387) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2575 + ... + 3204.

It is an arithmetic number, because the mean of its divisors is an integer number (150280).

2^1820385 is an apocalyptic number.

1820385 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1820385 is a deficient number, since it is larger than the sum of its proper divisors (1786335).

1820385 is a wasteful number, since it uses less digits than its factorization.

1820385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5797 (or 5794 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 1820385 is about 1349.2164392713. The cubic root of 1820385 is about 122.1015234835.

The spelling of 1820385 in words is "one million, eight hundred twenty thousand, three hundred eighty-five".