81134209 has 16 divisors (see below), whose sum is σ = 89775504. Its totient is φ = 72864000.

The previous prime is 81134197. The next prime is 81134231. The reversal of 81134209 is 90243118.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 23980609 + 57153600 = 4897^2 + 7560^2 .

It is a cyclic number.

It is not a de Polignac number, because 81134209 - 2⁵ = 81134177 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81134299) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79587 + ... + 80599.

It is an arithmetic number, because the mean of its divisors is an integer number (5610969).

Almost surely, 2^81134209 is an apocalyptic number.

It is an amenable number.

81134209 is a deficient number, since it is larger than the sum of its proper divisors (8641295).

81134209 is a wasteful number, since it uses less digits than its factorization.

81134209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1188.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 81134209 is about 9007.4529696247. The cubic root of 81134209 is about 432.9137057416.

The spelling of 81134209 in words is "eighty-one million, one hundred thirty-four thousand, two hundred nine".