123638 has 4 divisors (see below), whose sum is σ = 185460. Its totient is φ = 61818.

The previous prime is 123637. The next prime is 123653. The reversal of 123638 is 836321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 836321 = 269 ⋅3109.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123631) 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, 30908 + ... + 30911.

It is an arithmetic number, because the mean of its divisors is an integer number (46365).

2¹²³⁶³⁸ is an apocalyptic number.

123638 is a deficient number, since it is larger than the sum of its proper divisors (61822).

123638 is an equidigital number, since it uses as much as digits as its factorization.

123638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61821.

The product of its digits is 864, while the sum is 23.

The square root of 123638 is about 351.6219560835. The cubic root of 123638 is about 49.8177364070.

Adding to 123638 its reverse (836321), we get a palindrome (959959).

The spelling of 123638 in words is "one hundred twenty-three thousand, six hundred thirty-eight".