81308160 has 120 divisors (see below), whose sum is σ = 281672820. Its totient is φ = 21676032.

The previous prime is 81308137. The next prime is 81308173. The reversal of 81308160 is 6180318.

It can be written as a sum of positive squares in 2 ways, for example, as 73822464 + 7485696 = 8592^2 + 2736^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×81308160² = 13222033765171200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21276 + ... + 24804.

Almost surely, 2^81308160 is an apocalyptic number.

81308160 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 81308160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140836410).

81308160 is an abundant number, since it is smaller than the sum of its proper divisors (200364660).

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

81308160 is a wasteful number, since it uses less digits than its factorization.

81308160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3558 (or 3539 counting only the distinct ones).

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

The square root of 81308160 is about 9017.1037478783. The cubic root of 81308160 is about 433.2228725681. Note that the first 3 decimals are identical.

Adding to 81308160 its reverse (6180318), we get a palindrome (87488478).

It can be divided in two parts, 8130 and 8160, that added together give a triangular number (16290 = T₁₈₀).

The spelling of 81308160 in words is "eighty-one million, three hundred eight thousand, one hundred sixty".