81103680 has 336 divisors, whose sum is σ = 332841600. Its totient is φ = 18413568.

The previous prime is 81103619. The next prime is 81103721. The reversal of 81103680 is 8630118.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 544246 + ... + 544394.

It is an arithmetic number, because the mean of its divisors is an integer number (990600).

Almost surely, 2^81103680 is an apocalyptic number.

81103680 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 81103680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (166420800).

81103680 is an abundant number, since it is smaller than the sum of its proper divisors (251737920).

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

81103680 is a wasteful number, since it uses less digits than its factorization.

81103680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188 (or 166 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 81103680 is about 9005.7581579787. The cubic root of 81103680 is about 432.8594003271.

Adding to 81103680 its reverse (8630118), we get a palindrome (89733798).

The spelling of 81103680 in words is "eighty-one million, one hundred three thousand, six hundred eighty".