1820181 has 16 divisors (see below), whose sum is σ = 2787840. Its totient is φ = 1044720.

The previous prime is 1820171. The next prime is 1820201. The reversal of 1820181 is 1810281.

1820181 is nontrivially palindromic in base 9.

It is not a de Polignac number, because 1820181 - 2¹⁰ = 1819157 is a prime.

It is a super-2 number, since 2×1820181² = 6626117745522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820111) 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 15 ways as a sum of consecutive naturals, for example, 825 + ... + 2078.

It is an arithmetic number, because the mean of its divisors is an integer number (174240).

2^1820181 is an apocalyptic number.

1820181 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1820181 is a deficient number, since it is larger than the sum of its proper divisors (967659).

1820181 is a wasteful number, since it uses less digits than its factorization.

1820181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2936.

The product of its (nonzero) digits is 128, while the sum is 21.

The square root of 1820181 is about 1349.1408377186. The cubic root of 1820181 is about 122.0969622430.

The spelling of 1820181 in words is "one million, eight hundred twenty thousand, one hundred eighty-one".