81636852 has 48 divisors (see below), whose sum is σ = 210168000. Its totient is φ = 24456960.

The previous prime is 81636851. The next prime is 81636869. The reversal of 81636852 is 25863618.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81636852.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81636851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8274 + ... + 15222.

It is an arithmetic number, because the mean of its divisors is an integer number (4378500).

Almost surely, 2^81636852 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 81636852, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105084000).

81636852 is an abundant number, since it is smaller than the sum of its proper divisors (128531148).

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

81636852 is a wasteful number, since it uses less digits than its factorization.

81636852 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7056 (or 7054 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 81636852 is about 9035.3113947445. The cubic root of 81636852 is about 433.8058621893.

The spelling of 81636852 in words is "eighty-one million, six hundred thirty-six thousand, eight hundred fifty-two".