81722760 has 128 divisors (see below), whose sum is σ = 282009600. Its totient is φ = 18558720.

The previous prime is 81722651. The next prime is 81722777. The reversal of 81722760 is 6722718.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 227461 + ... + 227819.

It is an arithmetic number, because the mean of its divisors is an integer number (2203200).

Almost surely, 2^81722760 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 81722760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141004800).

81722760 is an abundant number, since it is smaller than the sum of its proper divisors (200286840).

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

81722760 is a wasteful number, since it uses less digits than its factorization.

81722760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651 (or 647 counting only the distinct ones).

The product of its (nonzero) digits is 9408, while the sum is 33.

The square root of 81722760 is about 9040.0641590644. The cubic root of 81722760 is about 433.9579762095.

The spelling of 81722760 in words is "eighty-one million, seven hundred twenty-two thousand, seven hundred sixty".