81133305 has 32 divisors (see below), whose sum is σ = 147778560. Its totient is φ = 37625280.

The previous prime is 81133289. The next prime is 81133309. The reversal of 81133305 is 50333118.

It is not a de Polignac number, because 81133305 - 2⁴ = 81133289 is a prime.

It is a super-2 number, since 2×81133305² = 13165226360446050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81133309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6895 + ... + 14484.

It is an arithmetic number, because the mean of its divisors is an integer number (4618080).

Almost surely, 2^81133305 is an apocalyptic number.

It is an amenable number.

81133305 is a deficient number, since it is larger than the sum of its proper divisors (66645255).

81133305 is a wasteful number, since it uses less digits than its factorization.

81133305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21421.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 81133305 is about 9007.4027888177. The cubic root of 81133305 is about 432.9120978895.

It can be divided in two parts, 81 and 133305, that added together give a triangular number (133386 = T₅₁₆).

The spelling of 81133305 in words is "eighty-one million, one hundred thirty-three thousand, three hundred five".