123016561 has 4 divisors (see below), whose sum is σ = 123136000. Its totient is φ = 122897124.

The previous prime is 123016511. The next prime is 123016577. The reversal of 123016561 is 165610321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165610321 = 10177 ⋅16273.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123016561 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123016511) 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, 58161 + ... + 60238.

It is an arithmetic number, because the mean of its divisors is an integer number (30784000).

Almost surely, 2^123016561 is an apocalyptic number.

It is an amenable number.

123016561 is a deficient number, since it is larger than the sum of its proper divisors (119439).

123016561 is a wasteful number, since it uses less digits than its factorization.

123016561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119438.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 123016561 is about 11091.2831088202. The cubic root of 123016561 is about 497.3413023785.

Adding to 123016561 its reverse (165610321), we get a palindrome (288626882).

The spelling of 123016561 in words is "one hundred twenty-three million, sixteen thousand, five hundred sixty-one".