81106500 has 96 divisors (see below), whose sum is σ = 238492800. Its totient is φ = 21417600.

The previous prime is 81106499. The next prime is 81106517. The reversal of 81106500 is 560118.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 208306 + ... + 208694.

It is an arithmetic number, because the mean of its divisors is an integer number (2484300).

Almost surely, 2^81106500 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 81106500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119246400).

81106500 is an abundant number, since it is smaller than the sum of its proper divisors (157386300).

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

81106500 is a wasteful number, since it uses less digits than its factorization.

81106500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 550 (or 538 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 81106500 is about 9005.9147231139. The cubic root of 81106500 is about 432.8644171540.

Adding to 81106500 its reverse (560118), we get a palindrome (81666618).

The spelling of 81106500 in words is "eighty-one million, one hundred six thousand, five hundred".