81580912 has 40 divisors (see below), whose sum is σ = 183620192. Its totient is φ = 34387200.

The previous prime is 81580879. The next prime is 81580913. The reversal of 81580912 is 21908518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81580913) 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, 862 + ... + 12802.

Almost surely, 2^81580912 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 81580912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91810096).

81580912 is an abundant number, since it is smaller than the sum of its proper divisors (102039280).

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

81580912 is a wasteful number, since it uses less digits than its factorization.

81580912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12017 (or 12011 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 81580912 is about 9032.2152321565. The cubic root of 81580912 is about 433.7067539872.

The spelling of 81580912 in words is "eighty-one million, five hundred eighty thousand, nine hundred twelve".