81655945929 has 24 divisors (see below), whose sum is σ = 124902353160. Its totient is φ = 51228215808.

The previous prime is 81655945927. The next prime is 81655945939. The reversal of 81655945929 is 92954955618.

81655945929 is a `hidden beast` number, since 8 + 1 + 6 + 559 + 4 + 59 + 29 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 678706704 + 80977239225 = 26052^2 + 284565^2 .

It is not a de Polignac number, because 81655945929 - 2¹ = 81655945927 is a prime.

It is a super-3 number, since 3×81655945929³ (a number of 34 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81655945927) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1257979 + ... + 1321295.

It is an arithmetic number, because the mean of its divisors is an integer number (5204264715).

Almost surely, 2^81655945929 is an apocalyptic number.

It is an amenable number.

81655945929 is a deficient number, since it is larger than the sum of its proper divisors (43246407231).

81655945929 is a wasteful number, since it uses less digits than its factorization.

81655945929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71769 (or 71766 counting only the distinct ones).

The product of its digits is 34992000, while the sum is 63.

The spelling of 81655945929 in words is "eighty-one billion, six hundred fifty-five million, nine hundred forty-five thousand, nine hundred twenty-nine".