81066636 has 96 divisors (see below), whose sum is σ = 242081280. Its totient is φ = 22980672.

The previous prime is 81066631. The next prime is 81066637. The reversal of 81066636 is 63666018.

81066636 is nontrivially palindromic in base 13.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 81066636.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81066631) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 118351 + ... + 119033.

It is an arithmetic number, because the mean of its divisors is an integer number (2521680).

Almost surely, 2^81066636 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 81066636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121040640).

81066636 is an abundant number, since it is smaller than the sum of its proper divisors (161014644).

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

81066636 is a wasteful number, since it uses less digits than its factorization.

81066636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860 (or 852 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 81066636 is about 9003.7012389350. The cubic root of 81066636 is about 432.7934876355.

The spelling of 81066636 in words is "eighty-one million, sixty-six thousand, six hundred thirty-six".