81854136 has 216 divisors, whose sum is σ = 283481640. Its totient is φ = 20891520.

The previous prime is 81854107. The next prime is 81854197. The reversal of 81854136 is 63145818.

81854136 is a `hidden beast` number, since 81 + 8 + 541 + 36 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 81854136.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 2640441 + ... + 2640471.

It is an arithmetic number, because the mean of its divisors is an integer number (1312415).

Almost surely, 2^81854136 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 81854136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141740820).

81854136 is an abundant number, since it is smaller than the sum of its proper divisors (201627504).

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

81854136 is a wasteful number, since it uses less digits than its factorization.

81854136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107 (or 56 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 81854136 is about 9047.3275612194. The cubic root of 81854136 is about 434.1903926544.

It can be divided in two parts, 8185 and 4136, that added together give a palindrome (12321).

The spelling of 81854136 in words is "eighty-one million, eight hundred fifty-four thousand, one hundred thirty-six".