123781840 has 160 divisors (see below), whose sum is σ = 362476800. Its totient is φ = 39062016.

The previous prime is 123781807. The next prime is 123781841. The reversal of 123781840 is 48187321.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 123781796 and 123781805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123781841) 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 in 31 ways as a sum of consecutive naturals, for example, 356547 + ... + 356893.

It is an arithmetic number, because the mean of its divisors is an integer number (2265480).

Almost surely, 2^123781840 is an apocalyptic number.

123781840 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 123781840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (181238400).

123781840 is an abundant number, since it is smaller than the sum of its proper divisors (238694960).

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

123781840 is a wasteful number, since it uses less digits than its factorization.

123781840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394 (or 374 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 123781840 is about 11125.7287401770. The cubic root of 123781840 is about 498.3704817766.

The spelling of 123781840 in words is "one hundred twenty-three million, seven hundred eighty-one thousand, eight hundred forty".