123440 has 20 divisors (see below), whose sum is σ = 287184. Its totient is φ = 49344.

The previous prime is 123439. The next prime is 123449. The reversal of 123440 is 44321.

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (123449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 692 + ... + 851.

2¹²³⁴⁴⁰ is an apocalyptic number.

123440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

123440 is an abundant number, since it is smaller than the sum of its proper divisors (163744).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

123440 is a wasteful number, since it uses less digits than its factorization.

123440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556 (or 1550 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 123440 is about 351.3402908862. The cubic root of 123440 is about 49.7911286704.

Adding to 123440 its reverse (44321), we get a palindrome (167761).

The spelling of 123440 in words is "one hundred twenty-three thousand, four hundred forty", and thus it is an iban number.