123305780 has 54 divisors (see below), whose sum is σ = 281868678. Its totient is φ = 45289920.

The previous prime is 123305779. The next prime is 123305789. The reversal of 123305780 is 87503321.

It can be written as a sum of positive squares in 3 ways, for example, as 583696 + 122722084 = 764^2 + 11078^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123305789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 645485 + ... + 645675.

Almost surely, 2^123305780 is an apocalyptic number.

123305780 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 123305780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140934339).

123305780 is an abundant number, since it is smaller than the sum of its proper divisors (158562898).

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

123305780 is a wasteful number, since it uses less digits than its factorization.

123305780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 123305780 is about 11104.3135762640. The cubic root of 123305780 is about 497.7307566498.

The spelling of 123305780 in words is "one hundred twenty-three million, three hundred five thousand, seven hundred eighty".