81166533 has 16 divisors (see below), whose sum is σ = 123895296. Its totient is φ = 46301040.

The previous prime is 81166513. The next prime is 81166549. The reversal of 81166533 is 33566118.

It is not a de Polignac number, because 81166533 - 2⁶ = 81166469 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81166494 and 81166503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81166513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10498 + ... + 16508.

It is an arithmetic number, because the mean of its divisors is an integer number (7743456).

Almost surely, 2^81166533 is an apocalyptic number.

It is an amenable number.

81166533 is a deficient number, since it is larger than the sum of its proper divisors (42728763).

81166533 is a wasteful number, since it uses less digits than its factorization.

81166533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6664.

The product of its digits is 12960, while the sum is 33.

The square root of 81166533 is about 9009.2470828588. The cubic root of 81166533 is about 432.9711892818.

The spelling of 81166533 in words is "eighty-one million, one hundred sixty-six thousand, five hundred thirty-three".