123216545 has 4 divisors (see below), whose sum is σ = 147859860. Its totient is φ = 98573232.

The previous prime is 123216503. The next prime is 123216547. The reversal of 123216545 is 545612321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 545612321 = 103 ⋅5297207.

It can be written as a sum of positive squares in 2 ways, for example, as 57395776 + 65820769 = 7576^2 + 8113^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123216545 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (123216547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12321650 + ... + 12321659.

It is an arithmetic number, because the mean of its divisors is an integer number (36964965).

Almost surely, 2^123216545 is an apocalyptic number.

It is an amenable number.

123216545 is a deficient number, since it is larger than the sum of its proper divisors (24643315).

123216545 is an equidigital number, since it uses as much as digits as its factorization.

123216545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24643314.

The product of its digits is 7200, while the sum is 29.

The square root of 123216545 is about 11100.2948159047. The cubic root of 123216545 is about 497.6106602991.

Adding to 123216545 its reverse (545612321), we get a palindrome (668828866).

The spelling of 123216545 in words is "one hundred twenty-three million, two hundred sixteen thousand, five hundred forty-five".