1820401 has 8 divisors (see below), whose sum is σ = 2013984. Its totient is φ = 1631520.

The previous prime is 1820389. The next prime is 1820407. The reversal of 1820401 is 1040281.

It is a happy number.

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

It is not a de Polignac number, because 1820401 - 2¹¹ = 1818353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1820407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 331 + ... + 1936.

It is an arithmetic number, because the mean of its divisors is an integer number (251748).

2^1820401 is an apocalyptic number.

1820401 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1820401 is a deficient number, since it is larger than the sum of its proper divisors (193583).

1820401 is a wasteful number, since it uses less digits than its factorization.

1820401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2351.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 1820401 is about 1349.2223686257. Note that the first 3 decimals coincide. The cubic root of 1820401 is about 122.1018812134.

Adding to 1820401 its reverse (1040281), we get a palindrome (2860682).

The spelling of 1820401 in words is "one million, eight hundred twenty thousand, four hundred one".