81265536 has 192 divisors, whose sum is σ = 262070640. Its totient is φ = 24161280.

The previous prime is 81265531. The next prime is 81265543. The reversal of 81265536 is 63556218.

81265536 is a `hidden beast` number, since 81 + 26 + 553 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

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 81265536.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81265531) 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, 1533286 + ... + 1533338.

Almost surely, 2^81265536 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 81265536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131035320).

81265536 is an abundant number, since it is smaller than the sum of its proper divisors (180805104).

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

81265536 is a wasteful number, since it uses less digits than its factorization.

81265536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106 (or 69 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 81265536 is about 9014.7399296929. The cubic root of 81265536 is about 433.1471568408.

The spelling of 81265536 in words is "eighty-one million, two hundred sixty-five thousand, five hundred thirty-six".