123789 has 4 divisors (see below), whose sum is σ = 165056. Its totient is φ = 82524.

The previous prime is 123787. The next prime is 123791. The reversal of 123789 is 987321.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (123787) and next prime (123791).

It is not a de Polignac number, because 123789 - 2¹ = 123787 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123787) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20629 + ... + 20634.

It is an arithmetic number, because the mean of its divisors is an integer number (41264).

2¹²³⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

123789 is a deficient number, since it is larger than the sum of its proper divisors (41267).

123789 is an equidigital number, since it uses as much as digits as its factorization.

123789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41266.

The product of its digits is 3024, while the sum is 30.

The square root of 123789 is about 351.8366098063. The cubic root of 123789 is about 49.8380090789.

It can be divided in two parts, 1237 and 89, that added together give a triangular number (1326 = T₅₁).

The spelling of 123789 in words is "one hundred twenty-three thousand, seven hundred eighty-nine".