81659673 has 24 divisors (see below), whose sum is σ = 122210816. Its totient is φ = 52488000.

The previous prime is 81659671. The next prime is 81659689. The reversal of 81659673 is 37695618.

It is a happy number.

It is not a de Polignac number, because 81659673 - 2¹ = 81659671 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81659671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 135573 + ... + 136173.

Almost surely, 2^81659673 is an apocalyptic number.

It is an amenable number.

81659673 is a deficient number, since it is larger than the sum of its proper divisors (40551143).

81659673 is a wasteful number, since it uses less digits than its factorization.

81659673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1125 (or 1122 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 81659673 is about 9036.5741849442. The cubic root of 81659673 is about 433.8462808687.

The spelling of 81659673 in words is "eighty-one million, six hundred fifty-nine thousand, six hundred seventy-three".