81075072 has 128 divisors (see below), whose sum is σ = 235620000. Its totient is φ = 24551424.

The previous prime is 81075067. The next prime is 81075073. The reversal of 81075072 is 27057018.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81075073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 544054 + ... + 544202.

Almost surely, 2^81075072 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 81075072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117810000).

81075072 is an abundant number, since it is smaller than the sum of its proper divisors (154544928).

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

81075072 is a wasteful number, since it uses less digits than its factorization.

81075072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288 (or 276 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 81075072 is about 9004.1697007553. The cubic root of 81075072 is about 432.8084996446.

The spelling of 81075072 in words is "eighty-one million, seventy-five thousand, seventy-two".