123105840 has 320 divisors, whose sum is σ = 476969472. Its totient is φ = 25804800.

The previous prime is 123105811. The next prime is 123105847. The reversal of 123105840 is 48501321.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 123105840.

It is not an unprimeable number, because it can be changed into a prime (123105847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 583335 + ... + 583545.

Almost surely, 2^123105840 is an apocalyptic number.

123105840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 123105840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (238484736).

123105840 is an abundant number, since it is smaller than the sum of its proper divisors (353863632).

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

123105840 is a wasteful number, since it uses less digits than its factorization.

123105840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 262 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 123105840 is about 11095.3071160739. The cubic root of 123105840 is about 497.4615880716.

The spelling of 123105840 in words is "one hundred twenty-three million, one hundred five thousand, eight hundred forty".