123320780521 has 2 divisors, whose sum is σ = 123320780522. Its totient is φ = 123320780520.

The previous prime is 123320780519. The next prime is 123320780563. The reversal of 123320780521 is 125087023321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79205659225 + 44115121296 = 281435^2 + 210036^2 .

It is a cyclic number.

It is not a de Polignac number, because 123320780521 - 2¹ = 123320780519 is a prime.

Together with 123320780519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (123320780501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61660390260 + 61660390261.

It is an arithmetic number, because the mean of its divisors is an integer number (61660390261).

Almost surely, 2^123320780521 is an apocalyptic number.

It is an amenable number.

123320780521 is a deficient number, since it is larger than the sum of its proper divisors (1).

123320780521 is an equidigital number, since it uses as much as digits as its factorization.

123320780521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 34.

The spelling of 123320780521 in words is "one hundred twenty-three billion, three hundred twenty million, seven hundred eighty thousand, five hundred twenty-one".