122156789 has 2 divisors, whose sum is σ = 122156790. Its totient is φ = 122156788.

The previous prime is 122156777. The next prime is 122156791. The reversal of 122156789 is 987651221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122102500 + 54289 = 11050^2 + 233^2 .

It is a cyclic number.

It is not a de Polignac number, because 122156789 - 2²⁰ = 121108213 is a prime.

Together with 122156791, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (122156189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61078394 + 61078395.

It is an arithmetic number, because the mean of its divisors is an integer number (61078395).

Almost surely, 2^122156789 is an apocalyptic number.

It is an amenable number.

122156789 is a deficient number, since it is larger than the sum of its proper divisors (1).

122156789 is an equidigital number, since it uses as much as digits as its factorization.

122156789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 41.

The square root of 122156789 is about 11052.4562428448. The cubic root of 122156789 is about 496.1799406201.

The spelling of 122156789 in words is "one hundred twenty-two million, one hundred fifty-six thousand, seven hundred eighty-nine".