81585277 has 2 divisors, whose sum is σ = 81585278. Its totient is φ = 81585276.

The previous prime is 81585271. The next prime is 81585289. The reversal of 81585277 is 77258518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41718681 + 39866596 = 6459^2 + 6314^2 .

It is a cyclic number.

It is not a de Polignac number, because 81585277 - 2³ = 81585269 is a prime.

It is a super-3 number, since 3×81585277³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81585271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40792638 + 40792639.

It is an arithmetic number, because the mean of its divisors is an integer number (40792639).

Almost surely, 2^81585277 is an apocalyptic number.

It is an amenable number.

81585277 is a deficient number, since it is larger than the sum of its proper divisors (1).

81585277 is an equidigital number, since it uses as much as digits as its factorization.

81585277 is an evil number, because the sum of its binary digits is even.

The product of its digits is 156800, while the sum is 43.

The square root of 81585277 is about 9032.4568639989. The cubic root of 81585277 is about 433.7144890328.

The spelling of 81585277 in words is "eighty-one million, five hundred eighty-five thousand, two hundred seventy-seven".