81171036 has 72 divisors (see below), whose sum is σ = 211555344. Its totient is φ = 26231040.

The previous prime is 81171031. The next prime is 81171047. The reversal of 81171036 is 63017118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81171031) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 175846 + ... + 176306.

Almost surely, 2^81171036 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 81171036, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105777672).

81171036 is an abundant number, since it is smaller than the sum of its proper divisors (130384308).

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

81171036 is a wasteful number, since it uses less digits than its factorization.

81171036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 611 (or 606 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 81171036 is about 9009.4969892886. The cubic root of 81171036 is about 432.9791960022.

The spelling of 81171036 in words is "eighty-one million, one hundred seventy-one thousand, thirty-six".