81133524 has 18 divisors (see below), whose sum is σ = 205087610. Its totient is φ = 27044496.

The previous prime is 81133523. The next prime is 81133529. The reversal of 81133524 is 42533118.

It is a happy number.

81133524 is a `hidden beast` number, since 8 + 1 + 133 + 524 = 666.

It can be written as a sum of positive squares in only one way, i.e., 41216400 + 39917124 = 6420^2 + 6318^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81133523) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1126819 + ... + 1126890.

Almost surely, 2^81133524 is an apocalyptic number.

It is an amenable number.

81133524 is an abundant number, since it is smaller than the sum of its proper divisors (123954086).

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

81133524 is a wasteful number, since it uses less digits than its factorization.

81133524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2253719 (or 2253714 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 81133524 is about 9007.4149454769. The cubic root of 81133524 is about 432.9124874034.

The spelling of 81133524 in words is "eighty-one million, one hundred thirty-three thousand, five hundred twenty-four".