81816966 has 120 divisors (see below), whose sum is σ = 232897896. Its totient is φ = 21228480.

The previous prime is 81816961. The next prime is 81816979. The reversal of 81816966 is 66961818.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81816961) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 86850 + ... + 87786.

Almost surely, 2^81816966 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81816966, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116448948).

81816966 is an abundant number, since it is smaller than the sum of its proper divisors (151080930).

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

81816966 is a wasteful number, since it uses less digits than its factorization.

81816966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 976 (or 960 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The square root of 81816966 is about 9045.2731302045. The cubic root of 81816966 is about 434.1246606862.

The spelling of 81816966 in words is "eighty-one million, eight hundred sixteen thousand, nine hundred sixty-six".