1816181 has 4 divisors (see below), whose sum is σ = 1821600. Its totient is φ = 1810764.

The previous prime is 1816159. The next prime is 1816187.

1816181 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1816181 - 2⁶ = 1816117 is a prime.

It is a super-2 number, since 2×1816181² = 6597026849522, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1816181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1816187) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2171 + ... + 2888.

It is an arithmetic number, because the mean of its divisors is an integer number (455400).

2^1816181 is an apocalyptic number.

It is an amenable number.

1816181 is a deficient number, since it is larger than the sum of its proper divisors (5419).

1816181 is an equidigital number, since it uses as much as digits as its factorization.

1816181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5418.

The product of its digits is 384, while the sum is 26.

The square root of 1816181 is about 1347.6575974631. The cubic root of 1816181 is about 122.0074572168.

The spelling of 1816181 in words is "one million, eight hundred sixteen thousand, one hundred eighty-one".