123391789 has 2 divisors, whose sum is σ = 123391790. Its totient is φ = 123391788.

The previous prime is 123391787. The next prime is 123391813. The reversal of 123391789 is 987193321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 122655625 + 736164 = 11075^2 + 858^2 .

It is a cyclic number.

It is not a de Polignac number, because 123391789 - 2¹ = 123391787 is a prime.

Together with 123391787, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123391787) 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 as a sum of consecutive naturals, namely, 61695894 + 61695895.

It is an arithmetic number, because the mean of its divisors is an integer number (61695895).

Almost surely, 2^123391789 is an apocalyptic number.

It is an amenable number.

123391789 is a deficient number, since it is larger than the sum of its proper divisors (1).

123391789 is an equidigital number, since it uses as much as digits as its factorization.

123391789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 43.

The square root of 123391789 is about 11108.1856754377. The cubic root of 123391789 is about 497.8464564841.

The spelling of 123391789 in words is "one hundred twenty-three million, three hundred ninety-one thousand, seven hundred eighty-nine".