81054540 has 192 divisors, whose sum is σ = 295787520. Its totient is φ = 18040320.

The previous prime is 81054517. The next prime is 81054557. The reversal of 81054540 is 4545018.

81054540 is a `hidden beast` number, since 81 + 0 + 545 + 40 = 666.

It is a super-2 number, since 2×81054540² = 13139676909223200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 154719 + ... + 155241.

It is an arithmetic number, because the mean of its divisors is an integer number (1540560).

Almost surely, 2^81054540 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 81054540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147893760).

81054540 is an abundant number, since it is smaller than the sum of its proper divisors (214732980).

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

81054540 is a wasteful number, since it uses less digits than its factorization.

81054540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589 (or 581 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 81054540 is about 9003.0294901216. The cubic root of 81054540 is about 432.7719607753.

Adding to 81054540 its reverse (4545018), we get a palindrome (85599558).

The spelling of 81054540 in words is "eighty-one million, fifty-four thousand, five hundred forty".