81655929 has 24 divisors (see below), whose sum is σ = 121642560. Its totient is φ = 52744608.

The previous prime is 81655927. The next prime is 81655943. The reversal of 81655929 is 92955618.

It is not a de Polignac number, because 81655929 - 2¹ = 81655927 is a prime.

It is a super-3 number, since 3×81655929³ (a number of 25 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (81655921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 125884 + ... + 126530.

It is an arithmetic number, because the mean of its divisors is an integer number (5068440).

Almost surely, 2^81655929 is an apocalyptic number.

It is an amenable number.

81655929 is a deficient number, since it is larger than the sum of its proper divisors (39986631).

81655929 is a wasteful number, since it uses less digits than its factorization.

81655929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1069 (or 1066 counting only the distinct ones).

The product of its digits is 194400, while the sum is 45.

The square root of 81655929 is about 9036.3670244186. The cubic root of 81655929 is about 433.8396503201.

The spelling of 81655929 in words is "eighty-one million, six hundred fifty-five thousand, nine hundred twenty-nine".