1800081 has 6 divisors (see below), whose sum is σ = 2600130. Its totient is φ = 1200048.

The previous prime is 1800067. The next prime is 1800083.

It is a happy number.

1800081 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 1134225 + 665856 = 1065^2 + 816^2 .

It is not a de Polignac number, because 1800081 - 2⁶ = 1800017 is a prime.

It is a super-2 number, since 2×1800081² = 6480583213122, which contains 22 as substring.

It is an Ulam number.

1800081 is a strobogrammatic number because it is the same when read upside-down.

1800081 is a modest number, since divided by 81 gives 18 as remainder.

It is not an unprimeable number, because it can be changed into a prime (1800083) 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 5 ways as a sum of consecutive naturals, for example, 99996 + ... + 100013.

It is an arithmetic number, because the mean of its divisors is an integer number (433355).

2^1800081 is an apocalyptic number.

It is an amenable number.

1800081 is a deficient number, since it is larger than the sum of its proper divisors (800049).

1800081 is a wasteful number, since it uses less digits than its factorization.

1800081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200015 (or 200012 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 1800081 is about 1341.6709730780. The cubic root of 1800081 is about 121.6458645447.

It can be divided in two parts, 18000 and 81, that added together give a palindrome (18081).

The spelling of 1800081 in words is "one million, eight hundred thousand, eighty-one".