81101280 has 192 divisors, whose sum is σ = 282719808. Its totient is φ = 19415040.

The previous prime is 81101263. The next prime is 81101281. The reversal of 81101280 is 8210118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81101281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 255682 + ... + 255998.

It is an arithmetic number, because the mean of its divisors is an integer number (1472499).

Almost surely, 2^81101280 is an apocalyptic number.

81101280 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 81101280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141359904).

81101280 is an abundant number, since it is smaller than the sum of its proper divisors (201618528).

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

81101280 is a wasteful number, since it uses less digits than its factorization.

81101280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389 (or 381 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 21.

The square root of 81101280 is about 9005.6249089111. The cubic root of 81101280 is about 432.8551305956.

Adding to 81101280 its reverse (8210118), we get a palindrome (89311398).

The spelling of 81101280 in words is "eighty-one million, one hundred one thousand, two hundred eighty".