81868 has 12 divisors (see below), whose sum is σ = 145432. Its totient is φ = 40320.

The previous prime is 81853. The next prime is 81869. The reversal of 81868 is 86818.

It is not an unprimeable number, because it can be changed into a prime (81869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 283 + ... + 493.

2⁸¹⁸⁶⁸ is an apocalyptic number.

It is an amenable number.

81868 is a deficient number, since it is larger than the sum of its proper divisors (63564).

81868 is a wasteful number, since it uses less digits than its factorization.

81868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312 (or 310 counting only the distinct ones).

The product of its digits is 3072, while the sum is 31.

The square root of 81868 is about 286.1258464382. The cubic root of 81868 is about 43.4214904858.

Subtracting 81868 from its reverse (86818), we obtain a triangular number (4950 = T₉₉).

It can be divided in two parts, 81 and 868, that added together give a palindrome (949).

The spelling of 81868 in words is "eighty-one thousand, eight hundred sixty-eight".