81135936 has 84 divisors (see below), whose sum is σ = 265797792. Its totient is φ = 23180544.

The previous prime is 81135919. The next prime is 81135937. The reversal of 81135936 is 63953118.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (84).

It is a super-2 number, since 2×81135936² = 13166080221192192, which contains 22 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 81135936.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81135937) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6030 + ... + 14093.

Almost surely, 2^81135936 is an apocalyptic number.

It is an amenable number.

81135936 is an abundant number, since it is smaller than the sum of its proper divisors (184661856).

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

81135936 is a wasteful number, since it uses less digits than its factorization.

81135936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20148 (or 20135 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 81135936 is about 9007.5488341724. The cubic root of 81135936 is about 432.9167773464.

The spelling of 81135936 in words is "eighty-one million, one hundred thirty-five thousand, nine hundred thirty-six".