81655277 has 6 divisors (see below), whose sum is σ = 89753454. Its totient is φ = 74231960.

The previous prime is 81655253. The next prime is 81655283. The reversal of 81655277 is 77255618.

It can be written as a sum of positive squares in only one way, i.e., 48177481 + 33477796 = 6941^2 + 5786^2 .

It is not a de Polignac number, because 81655277 - 2¹⁸ = 81393133 is a prime.

It is a super-3 number, since 3×81655277³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81655247) 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 5 ways as a sum of consecutive naturals, for example, 337298 + ... + 337539.

It is an arithmetic number, because the mean of its divisors is an integer number (14958909).

Almost surely, 2^81655277 is an apocalyptic number.

It is an amenable number.

81655277 is a deficient number, since it is larger than the sum of its proper divisors (8098177).

81655277 is a wasteful number, since it uses less digits than its factorization.

81655277 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 674859 (or 674848 counting only the distinct ones).

The product of its digits is 117600, while the sum is 41.

The square root of 81655277 is about 9036.3309479014. The cubic root of 81655277 is about 433.8384956205.

The spelling of 81655277 in words is "eighty-one million, six hundred fifty-five thousand, two hundred seventy-seven".