81130880 has 64 divisors (see below), whose sum is σ = 195901200. Its totient is φ = 32126976.

The previous prime is 81130877. The next prime is 81130921. The reversal of 81130880 is 8803118.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69179 + ... + 70341.

Almost surely, 2^81130880 is an apocalyptic number.

81130880 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 81130880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97950600).

81130880 is an abundant number, since it is smaller than the sum of its proper divisors (114770320).

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

81130880 is a wasteful number, since it uses less digits than its factorization.

81130880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1291 (or 1279 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 29.

The square root of 81130880 is about 9007.2681763118. The cubic root of 81130880 is about 432.9077847314.

Adding to 81130880 its reverse (8803118), we get a palindrome (89933998).

The spelling of 81130880 in words is "eighty-one million, one hundred thirty thousand, eight hundred eighty".