81732609 has 24 divisors (see below), whose sum is σ = 135844800. Its totient is φ = 46385568.

The previous prime is 81732589. The next prime is 81732613. The reversal of 81732609 is 90623718.

81732609 is a `hidden beast` number, since 8 + 17 + 32 + 609 = 666.

It is not a de Polignac number, because 81732609 - 2¹² = 81728513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81732649) 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 23 ways as a sum of consecutive naturals, for example, 5034 + ... + 13740.

It is an arithmetic number, because the mean of its divisors is an integer number (5660200).

Almost surely, 2^81732609 is an apocalyptic number.

It is an amenable number.

81732609 is a deficient number, since it is larger than the sum of its proper divisors (54112191).

81732609 is a wasteful number, since it uses less digits than its factorization.

81732609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8869 (or 8866 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 81732609 is about 9040.6088843617. The cubic root of 81732609 is about 433.9754086458.

The spelling of 81732609 in words is "eighty-one million, seven hundred thirty-two thousand, six hundred nine".