81706560 has 112 divisors (see below), whose sum is σ = 279416256. Its totient is φ = 20109312.

The previous prime is 81706523. The next prime is 81706561. The reversal of 81706560 is 6560718.

It is not an unprimeable number, because it can be changed into a prime (81706561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9207 + ... + 15753.

It is an arithmetic number, because the mean of its divisors is an integer number (2494788).

Almost surely, 2^81706560 is an apocalyptic number.

81706560 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81706560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139708128).

81706560 is an abundant number, since it is smaller than the sum of its proper divisors (197709696).

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

81706560 is a wasteful number, since it uses less digits than its factorization.

81706560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6580 (or 6570 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 33.

The square root of 81706560 is about 9039.1681033157. The cubic root of 81706560 is about 433.9292996458.

The spelling of 81706560 in words is "eighty-one million, seven hundred six thousand, five hundred sixty".