123866 has 4 divisors (see below), whose sum is σ = 185802. Its totient is φ = 61932.

The previous prime is 123863. The next prime is 123887. The reversal of 123866 is 668321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 668321 = 17 ⋅39313.

It can be written as a sum of positive squares in only one way, i.e., 108241 + 15625 = 329^2 + 125^2 .

It is not an unprimeable number, because it can be changed into a prime (123863) 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 as a sum of consecutive naturals, namely, 30965 + ... + 30968.

2¹²³⁸⁶⁶ is an apocalyptic number.

123866 is a deficient number, since it is larger than the sum of its proper divisors (61936).

123866 is an equidigital number, since it uses as much as digits as its factorization.

123866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61935.

The product of its digits is 1728, while the sum is 26.

The square root of 123866 is about 351.9460185881. The cubic root of 123866 is about 49.8483404527.

It can be divided in two parts, 123 and 866, that added together give a palindrome (989).

The spelling of 123866 in words is "one hundred twenty-three thousand, eight hundred sixty-six".