82781 has 2 divisors, whose sum is σ = 82782. Its totient is φ = 82780.

The previous prime is 82763. The next prime is 82787. The reversal of 82781 is 18728.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55225 + 27556 = 235^2 + 166^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-82781 is a prime.

It is a super-2 number, since 2×82781² = 13705387922, which contains 22 as substring.

It is a Chen prime.

It is a plaindrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 82781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (82787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41390 + 41391.

It is an arithmetic number, because the mean of its divisors is an integer number (41391).

2⁸²⁷⁸¹ is an apocalyptic number.

It is an amenable number.

82781 is a deficient number, since it is larger than the sum of its proper divisors (1).

82781 is an equidigital number, since it uses as much as digits as its factorization.

82781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 896, while the sum is 26.

The square root of 82781 is about 287.7168747224. The cubic root of 82781 is about 43.5823077222.

The spelling of 82781 in words is "eighty-two thousand, seven hundred eighty-one".