81065040 has 160 divisors (see below), whose sum is σ = 291576576. Its totient is φ = 18247680.

The previous prime is 81065011. The next prime is 81065051. The reversal of 81065040 is 4056018.

It is a super-3 number, since 3×81065040³ (a number of 25 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 81065040.

It is a congruent number.

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, 122310 + ... + 122970.

Almost surely, 2^81065040 is an apocalyptic number.

81065040 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 81065040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145788288).

81065040 is an abundant number, since it is smaller than the sum of its proper divisors (210511536).

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

81065040 is a wasteful number, since it uses less digits than its factorization.

81065040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 757 (or 751 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 81065040 is about 9003.6126082812. The cubic root of 81065040 is about 432.7906474085.

The spelling of 81065040 in words is "eighty-one million, sixty-five thousand, forty".