778123 has 2 divisors, whose sum is σ = 778124. Its totient is φ = 778122.

The previous prime is 778121. The next prime is 778153. The reversal of 778123 is 321877.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 778123 - 2¹ = 778121 is a prime.

Together with 778121, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 778091 and 778100.

It is not a weakly prime, because it can be changed into another prime (778121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 389061 + 389062.

It is an arithmetic number, because the mean of its divisors is an integer number (389062).

2⁷⁷⁸¹²³ is an apocalyptic number.

778123 is a deficient number, since it is larger than the sum of its proper divisors (1).

778123 is an equidigital number, since it uses as much as digits as its factorization.

778123 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2352, while the sum is 28.

The square root of 778123 is about 882.1128045777. The cubic root of 778123 is about 91.9777435135.

It can be divided in two parts, 77812 and 3, that added together give a triangular number (77815 = T₃₉₄).

The spelling of 778123 in words is "seven hundred seventy-eight thousand, one hundred twenty-three".