81005472 has 72 divisors (see below), whose sum is σ = 233575524. Its totient is φ = 26625024.

The previous prime is 81005467. The next prime is 81005501. The reversal of 81005472 is 27450018.

It can be written as a sum of positive squares in 2 ways, for example, as 69956496 + 11048976 = 8364^2 + 3324^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19098 + ... + 22950.

Almost surely, 2^81005472 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 81005472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116787762).

81005472 is an abundant number, since it is smaller than the sum of its proper divisors (152570052).

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

81005472 is a wasteful number, since it uses less digits than its factorization.

81005472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3942 (or 3931 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 81005472 is about 9000.3039948660. The cubic root of 81005472 is about 432.6846140699.

The spelling of 81005472 in words is "eighty-one million, five thousand, four hundred seventy-two".