81302560 has 48 divisors (see below), whose sum is σ = 192893400. Its totient is φ = 32382976.

The previous prime is 81302521. The next prime is 81302581. The reversal of 81302560 is 6520318.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 44675856 + 36626704 = 6684^2 + 6052^2 .

It is a super-2 number, since 2×81302560² = 13220212525107200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42096 + ... + 43984.

Almost surely, 2^81302560 is an apocalyptic number.

81302560 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 81302560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96446700).

81302560 is an abundant number, since it is smaller than the sum of its proper divisors (111590840).

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

81302560 is a wasteful number, since it uses less digits than its factorization.

81302560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2173 (or 2165 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 81302560 is about 9016.7932215395. The cubic root of 81302560 is about 433.2129264414.

Adding to 81302560 its reverse (6520318), we get a palindrome (87822878).

The spelling of 81302560 in words is "eighty-one million, three hundred two thousand, five hundred sixty".