81258580 has 72 divisors (see below), whose sum is σ = 191381400. Its totient is φ = 28933632.

The previous prime is 81258557. The next prime is 81258607. The reversal of 81258580 is 8585218.

It can be written as a sum of positive squares in 12 ways, for example, as 42146064 + 39112516 = 6492^2 + 6254^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 97606 + ... + 98434.

It is an arithmetic number, because the mean of its divisors is an integer number (2658075).

Almost surely, 2^81258580 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81258580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95690700).

81258580 is an abundant number, since it is smaller than the sum of its proper divisors (110122820).

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

81258580 is a wasteful number, since it uses less digits than its factorization.

81258580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 893 (or 878 counting only the distinct ones).

The product of its (nonzero) digits is 25600, while the sum is 37.

The square root of 81258580 is about 9014.3541088644. The cubic root of 81258580 is about 433.1347979421.

The spelling of 81258580 in words is "eighty-one million, two hundred fifty-eight thousand, five hundred eighty".