123781855 has 4 divisors (see below), whose sum is σ = 148538232. Its totient is φ = 99025480.

The previous prime is 123781849. The next prime is 123781859. The reversal of 123781855 is 558187321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 558187321 = 22697 ⋅24593.

It is a de Polignac number, because none of the positive numbers 2^k-123781855 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123781859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12378181 + ... + 12378190.

It is an arithmetic number, because the mean of its divisors is an integer number (37134558).

Almost surely, 2^123781855 is an apocalyptic number.

123781855 is a deficient number, since it is larger than the sum of its proper divisors (24756377).

123781855 is an equidigital number, since it uses as much as digits as its factorization.

123781855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24756376.

The product of its digits is 67200, while the sum is 40.

The square root of 123781855 is about 11125.7294142901. The cubic root of 123781855 is about 498.3705019076.

The spelling of 123781855 in words is "one hundred twenty-three million, seven hundred eighty-one thousand, eight hundred fifty-five".