81781627 has 8 divisors (see below), whose sum is σ = 84863360. Its totient is φ = 78727680.

The previous prime is 81781621. The next prime is 81781631. The reversal of 81781627 is 72618718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81781627 - 2¹⁹ = 81257339 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81781627.

It is not an unprimeable number, because it can be changed into a prime (81781621) 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 7 ways as a sum of consecutive naturals, for example, 852 + ... + 12817.

It is an arithmetic number, because the mean of its divisors is an integer number (10607920).

Almost surely, 2^81781627 is an apocalyptic number.

81781627 is a deficient number, since it is larger than the sum of its proper divisors (3081733).

81781627 is a wasteful number, since it uses less digits than its factorization.

81781627 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13893.

The product of its digits is 37632, while the sum is 40.

The square root of 81781627 is about 9043.3194679830. The cubic root of 81781627 is about 434.0621482209.

The spelling of 81781627 in words is "eighty-one million, seven hundred eighty-one thousand, six hundred twenty-seven".