81810036 has 108 divisors (see below), whose sum is σ = 259875616. Its totient is φ = 21241440.

The previous prime is 81810019. The next prime is 81810041. The reversal of 81810036 is 63001818.

It is a junction number, because it is equal to n+sod(n) for n = 81809991 and 81810009.

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 29151 + ... + 31833.

Almost surely, 2^81810036 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81810036, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129937808).

81810036 is an abundant number, since it is smaller than the sum of its proper divisors (178065580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81810036 is a wasteful number, since it uses less digits than its factorization.

81810036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2722 (or 2706 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 81810036 is about 9044.8900490830. The cubic root of 81810036 is about 434.1124033717.

The spelling of 81810036 in words is "eighty-one million, eight hundred ten thousand, thirty-six".