81044100 has 108 divisors (see below), whose sum is σ = 269021844. Its totient is φ = 20336640.

The previous prime is 81044081. The next prime is 81044113. The reversal of 81044100 is 144018.

It can be written as a sum of positive squares in 6 ways, for example, as 2509056 + 78535044 = 1584^2 + 8862^2 .

It is a super-2 number, since 2×81044100² = 13136292289620000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 12652 + ... + 17948.

It is an arithmetic number, because the mean of its divisors is an integer number (2490943).

Almost surely, 2^81044100 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 81044100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134510922).

81044100 is an abundant number, since it is smaller than the sum of its proper divisors (187977744).

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

81044100 is a wasteful number, since it uses less digits than its factorization.

81044100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5334 (or 5324 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 81044100 is about 9002.4496666185. The cubic root of 81044100 is about 432.7533793228.

Adding to 81044100 its reverse (144018), we get a palindrome (81188118).

The spelling of 81044100 in words is "eighty-one million, forty-four thousand, one hundred".