81330000 has 100 divisors (see below), whose sum is σ = 262640928. Its totient is φ = 21680000.

The previous prime is 81329993. The next prime is 81330017. The reversal of 81330000 is 3318.

It is a tau number, because it is divible by the number of its divisors (100).

It is a super-2 number, since 2×81330000² = 13229137800000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 28645 + ... + 31355.

Almost surely, 2^81330000 is an apocalyptic number.

81330000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81330000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131320464).

81330000 is an abundant number, since it is smaller than the sum of its proper divisors (181310928).

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

81330000 is a wasteful number, since it uses less digits than its factorization.

81330000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2742 (or 2721 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 81330000 is about 9018.3146984345. The cubic root of 81330000 is about 433.2616580992.

Adding to 81330000 its reverse (3318), we get a palindrome (81333318).

The spelling of 81330000 in words is "eighty-one million, three hundred thirty thousand".