123505999999 has 4 divisors (see below), whose sum is σ = 123510701664. Its totient is φ = 123501298336.

The previous prime is 123505999997. The next prime is 123506000041. The reversal of 123505999999 is 999999505321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 999999505321 = 17 ⋅58823500313.

It is a cyclic number.

It is not a de Polignac number, because 123505999999 - 2¹ = 123505999997 is a prime.

It is a Duffinian number.

123505999999 is a modest number, since divided by 999999 gives 123505 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123505999993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2311207 + ... + 2364040.

It is an arithmetic number, because the mean of its divisors is an integer number (30877675416).

Almost surely, 2^123505999999 is an apocalyptic number.

123505999999 is a deficient number, since it is larger than the sum of its proper divisors (4701665).

123505999999 is an equidigital number, since it uses as much as digits as its factorization.

123505999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4701664.

The product of its (nonzero) digits is 79716150, while the sum is 70.

The spelling of 123505999999 in words is "one hundred twenty-three billion, five hundred five million, nine hundred ninety-nine thousand, nine hundred ninety-nine".