812181 has 8 divisors (see below), whose sum is σ = 1094464. Its totient is φ = 535680.

The previous prime is 812179. The next prime is 812183. The reversal of 812181 is 181218.

It is an interprime number because it is at equal distance from previous prime (812179) and next prime (812183).

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

It is not a de Polignac number, because 812181 - 2¹ = 812179 is a prime.

It is a super-2 number, since 2×812181² = 1319275953522, which contains 22 as substring.

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

It is a Duffinian number.

812181 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (812183) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1105 + ... + 1686.

It is an arithmetic number, because the mean of its divisors is an integer number (136808).

2⁸¹²¹⁸¹ is an apocalyptic number.

It is an amenable number.

812181 is a deficient number, since it is larger than the sum of its proper divisors (282283).

812181 is a wasteful number, since it uses less digits than its factorization.

812181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2891.

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

The square root of 812181 is about 901.2108521317. The cubic root of 812181 is about 93.3005653110.

Adding to 812181 its reverse (181218), we get a palindrome (993399).

The spelling of 812181 in words is "eight hundred twelve thousand, one hundred eighty-one".