81841536 has 256 divisors, whose sum is σ = 293760000. Its totient is φ = 21897216.

The previous prime is 81841517. The next prime is 81841537. The reversal of 81841536 is 63514818.

81841536 is a `hidden beast` number, since 81 + 8 + 41 + 536 = 666.

It is a super-3 number, since 3×81841536³ (a number of 25 digits) contains 333 as substring.

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 81841536.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81841537) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 411165 + ... + 411363.

It is an arithmetic number, because the mean of its divisors is an integer number (1147500).

Almost surely, 2^81841536 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 81841536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146880000).

81841536 is an abundant number, since it is smaller than the sum of its proper divisors (211918464).

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

81841536 is a wasteful number, since it uses less digits than its factorization.

81841536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 228 counting only the distinct ones).

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

The square root of 81841536 is about 9046.6311961967. The cubic root of 81841536 is about 434.1681128611.

The spelling of 81841536 in words is "eighty-one million, eight hundred forty-one thousand, five hundred thirty-six".