81471312 has 160 divisors (see below), whose sum is σ = 256233600. Its totient is φ = 24634368.

The previous prime is 81471311. The next prime is 81471349. The reversal of 81471312 is 21317418.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81471311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 499743 + ... + 499905.

It is an arithmetic number, because the mean of its divisors is an integer number (1601460).

Almost surely, 2^81471312 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 81471312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128116800).

81471312 is an abundant number, since it is smaller than the sum of its proper divisors (174762288).

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

81471312 is a wasteful number, since it uses less digits than its factorization.

81471312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282 (or 270 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 81471312 is about 9026.1460214202. The cubic root of 81471312 is about 433.5124456144.

The spelling of 81471312 in words is "eighty-one million, four hundred seventy-one thousand, three hundred twelve".