81733536 has 144 divisors (see below), whose sum is σ = 252068544. Its totient is φ = 26002944.

The previous prime is 81733523. The next prime is 81733537. The reversal of 81733536 is 63533718.

It is a tau number, because it is divible by the number of its divisors (144).

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 81733536.

It is not an unprimeable number, because it can be changed into a prime (81733537) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 178620 + ... + 179076.

It is an arithmetic number, because the mean of its divisors is an integer number (1750476).

Almost surely, 2^81733536 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 81733536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126034272).

81733536 is an abundant number, since it is smaller than the sum of its proper divisors (170335008).

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

81733536 is a wasteful number, since it uses less digits than its factorization.

81733536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505 (or 485 counting only the distinct ones).

The product of its digits is 45360, while the sum is 36.

The square root of 81733536 is about 9040.6601528871. The cubic root of 81733536 is about 433.9770493360.

The spelling of 81733536 in words is "eighty-one million, seven hundred thirty-three thousand, five hundred thirty-six".