81147072 has 56 divisors (see below), whose sum is σ = 215652096. Its totient is φ = 26929408.

The previous prime is 81147071. The next prime is 81147089. The reversal of 81147072 is 27074118.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81147071) 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 7 ways as a sum of consecutive naturals, for example, 49693 + ... + 51299.

Almost surely, 2^81147072 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 81147072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107826048).

81147072 is an abundant number, since it is smaller than the sum of its proper divisors (134505024).

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

81147072 is a wasteful number, since it uses less digits than its factorization.

81147072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1885 (or 1875 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 81147072 is about 9008.1669611525. The cubic root of 81147072 is about 432.9365825479.

It can be divided in two parts, 81 and 147072, that added together give a triangular number (147153 = T₅₄₂).

The spelling of 81147072 in words is "eighty-one million, one hundred forty-seven thousand, seventy-two".