81147040 has 72 divisors (see below), whose sum is σ = 207660348. Its totient is φ = 29952000.

The previous prime is 81146993. The next prime is 81147041. The reversal of 81147040 is 4074118.

It can be written as a sum of positive squares in 6 ways, for example, as 9168784 + 71978256 = 3028^2 + 8484^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81146996 and 81147014.

It is not an unprimeable number, because it can be changed into a prime (81147041) 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 11 ways as a sum of consecutive naturals, for example, 25540 + ... + 28540.

Almost surely, 2^81147040 is an apocalyptic number.

81147040 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 81147040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103830174).

81147040 is an abundant number, since it is smaller than the sum of its proper divisors (126513308).

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

81147040 is a wasteful number, since it uses less digits than its factorization.

81147040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3042 (or 3021 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 81147040 is about 9008.1651849863. The cubic root of 81147040 is about 432.9365256390.

The spelling of 81147040 in words is "eighty-one million, one hundred forty-seven thousand, forty".