123642890689 has 4 divisors (see below), whose sum is σ = 130916001924. Its totient is φ = 116369779456.

The previous prime is 123642890681. The next prime is 123642890719. The reversal of 123642890689 is 986098246321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 986098246321 = 311 ⋅3170733911.

It can be written as a sum of positive squares in 2 ways, for example, as 56617823025 + 67025067664 = 237945^2 + 258892^2 .

It is a cyclic number.

It is not a de Polignac number, because 123642890689 - 2³ = 123642890681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123642890681) 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 in 3 ways as a sum of consecutive naturals, for example, 3636555592 + ... + 3636555625.

It is an arithmetic number, because the mean of its divisors is an integer number (32729000481).

Almost surely, 2^123642890689 is an apocalyptic number.

It is an amenable number.

123642890689 is a deficient number, since it is larger than the sum of its proper divisors (7273111235).

123642890689 is an equidigital number, since it uses as much as digits as its factorization.

123642890689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7273111234.

The product of its (nonzero) digits is 8957952, while the sum is 58.

The spelling of 123642890689 in words is "one hundred twenty-three billion, six hundred forty-two million, eight hundred ninety thousand, six hundred eighty-nine".