81408560 has 20 divisors (see below), whose sum is σ = 189275088. Its totient is φ = 32563392.

The previous prime is 81408553. The next prime is 81408577. The reversal of 81408560 is 6580418.

It is a tau number, because it is divible by the number of its divisors (20).

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 3 ways as a sum of consecutive naturals, for example, 508724 + ... + 508883.

Almost surely, 2^81408560 is an apocalyptic number.

81408560 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81408560 is an abundant number, since it is smaller than the sum of its proper divisors (107866528).

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

81408560 is a wasteful number, since it uses less digits than its factorization.

81408560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1017620 (or 1017614 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 81408560 is about 9022.6692281165. The cubic root of 81408560 is about 433.4011149724.

Adding to 81408560 its reverse (6580418), we get a palindrome (87988978).

The spelling of 81408560 in words is "eighty-one million, four hundred eight thousand, five hundred sixty".