81288580 has 24 divisors (see below), whose sum is σ = 171035928. Its totient is φ = 32452608.

The previous prime is 81288569. The next prime is 81288583. The reversal of 81288580 is 8588218.

It can be written as a sum of positive squares in 4 ways, for example, as 324 + 81288256 = 18^2 + 9016^2 .

It is not an unprimeable number, because it can be changed into a prime (81288583) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7492 + ... + 14788.

It is an arithmetic number, because the mean of its divisors is an integer number (7126497).

Almost surely, 2^81288580 is an apocalyptic number.

It is an amenable number.

81288580 is an abundant number, since it is smaller than the sum of its proper divisors (89747348).

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

81288580 is a wasteful number, since it uses less digits than its factorization.

81288580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7863 (or 7861 counting only the distinct ones).

The product of its (nonzero) digits is 40960, while the sum is 40.

The square root of 81288580 is about 9016.0179680389. The cubic root of 81288580 is about 433.1880946531.

The spelling of 81288580 in words is "eighty-one million, two hundred eighty-eight thousand, five hundred eighty".