1820001 has 8 divisors (see below), whose sum is σ = 2437344. Its totient is φ = 1208000.

The previous prime is 1819999. The next prime is 1820009. The reversal of 1820001 is 1000281.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1820001 - 2¹ = 1819999 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1820009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 456 + ... + 1961.

It is an arithmetic number, because the mean of its divisors is an integer number (304668).

2^1820001 is an apocalyptic number.

It is an amenable number.

1820001 is a deficient number, since it is larger than the sum of its proper divisors (617343).

1820001 is a wasteful number, since it uses less digits than its factorization.

1820001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2671.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1820001 is about 1349.0741269478. The cubic root of 1820001 is about 122.0929373360.

Adding to 1820001 its reverse (1000281), we get a palindrome (2820282).

The spelling of 1820001 in words is "one million, eight hundred twenty thousand, one".