1800181 has 6 divisors (see below), whose sum is σ = 1912610. Its totient is φ = 1694016.

The previous prime is 1800179. The next prime is 1800191. The reversal of 1800181 is 1810081.

1800181 = T₁₀₉₄ + T₁₀₉₅ + T₁₀₉₆.

It can be written as a sum of positive squares in 3 ways, for example, as 731025 + 1069156 = 855^2 + 1034^2 .

It is not a de Polignac number, because 1800181 - 2¹ = 1800179 is a prime.

It is a super-2 number, since 2×1800181² = 6481303265522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1800121) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2826 + ... + 3403.

2^1800181 is an apocalyptic number.

1800181 is the 1096-th centered triangular number.

It is an amenable number.

1800181 is a deficient number, since it is larger than the sum of its proper divisors (112429).

1800181 is an equidigital number, since it uses as much as digits as its factorization.

1800181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6263 (or 6246 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 19.

The square root of 1800181 is about 1341.7082395215. The cubic root of 1800181 is about 121.6481171028.

The spelling of 1800181 in words is "one million, eight hundred thousand, one hundred eighty-one".