81852181 has 8 divisors (see below), whose sum is σ = 84775680. Its totient is φ = 78935472.

The previous prime is 81852167. The next prime is 81852223. The reversal of 81852181 is 18125818.

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

It is a cyclic number.

It is not a de Polignac number, because 81852181 - 2⁵ = 81852149 is a prime.

It is a super-4 number, since 4×81852181⁴ (a number of 33 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81852131) 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, 45016 + ... + 46798.

It is an arithmetic number, because the mean of its divisors is an integer number (10596960).

Almost surely, 2^81852181 is an apocalyptic number.

It is an amenable number.

81852181 is a deficient number, since it is larger than the sum of its proper divisors (2923499).

81852181 is a wasteful number, since it uses less digits than its factorization.

81852181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3395.

The product of its digits is 5120, while the sum is 34.

The square root of 81852181 is about 9047.2195176198. The cubic root of 81852181 is about 434.1869358998.

Adding to 81852181 its reverse (18125818), we get a palindrome (99977999).

The spelling of 81852181 in words is "eighty-one million, eight hundred fifty-two thousand, one hundred eighty-one".