81803181 has 8 divisors (see below), whose sum is σ = 110699104. Its totient is φ = 53721360.

The previous prime is 81803177. The next prime is 81803207. The reversal of 81803181 is 18130818.

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

It is not a de Polignac number, because 81803181 - 2² = 81803177 is a prime.

It is a super-2 number, since 2×81803181² = 13383520843437522, 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 (81803101) 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, 203290 + ... + 203691.

It is an arithmetic number, because the mean of its divisors is an integer number (13837388).

Almost surely, 2^81803181 is an apocalyptic number.

It is an amenable number.

81803181 is a deficient number, since it is larger than the sum of its proper divisors (28895923).

81803181 is a wasteful number, since it uses less digits than its factorization.

81803181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407051.

The product of its (nonzero) digits is 1536, while the sum is 30.

The square root of 81803181 is about 9044.5110978980. The cubic root of 81803181 is about 434.1002780311.

Adding to 81803181 its reverse (18130818), we get a palindrome (99933999).

The spelling of 81803181 in words is "eighty-one million, eight hundred three thousand, one hundred eighty-one".