81530000 has 100 divisors (see below), whose sum is σ = 204534528. Its totient is φ = 31440000.

The previous prime is 81529993. The next prime is 81530051. The reversal of 81530000 is 3518.

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

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, 309869 + ... + 310131.

Almost surely, 2^81530000 is an apocalyptic number.

81530000 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 81530000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102267264).

81530000 is an abundant number, since it is smaller than the sum of its proper divisors (123004528).

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

81530000 is a wasteful number, since it uses less digits than its factorization.

81530000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322 (or 301 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 81530000 is about 9029.3964360859. The cubic root of 81530000 is about 433.6165144421.

Adding to 81530000 its reverse (3518), we get a palindrome (81533518).

The spelling of 81530000 in words is "eighty-one million, five hundred thirty thousand".