81566080 has 32 divisors (see below), whose sum is σ = 194995440. Its totient is φ = 32626176.

The previous prime is 81566071. The next prime is 81566083. The reversal of 81566080 is 8066518.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81566083) by changing a digit.

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, 63084 + ... + 64363.

Almost surely, 2^81566080 is an apocalyptic number.

81566080 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81566080 is an abundant number, since it is smaller than the sum of its proper divisors (113429360).

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

81566080 is a wasteful number, since it uses less digits than its factorization.

81566080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127466 (or 127454 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 81566080 is about 9031.3941337979. The cubic root of 81566080 is about 433.6804687190.

The spelling of 81566080 in words is "eighty-one million, five hundred sixty-six thousand, eighty".