123100561 has 4 divisors (see below), whose sum is σ = 123123312. Its totient is φ = 123077812.

The previous prime is 123100559. The next prime is 123100583. The reversal of 123100561 is 165001321.

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: 165001321 = 127 ⋅1299223.

It is a cyclic number.

It is not a de Polignac number, because 123100561 - 2¹ = 123100559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123104561) 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, 1926 + ... + 15808.

It is an arithmetic number, because the mean of its divisors is an integer number (30780828).

Almost surely, 2^123100561 is an apocalyptic number.

It is an amenable number.

123100561 is a deficient number, since it is larger than the sum of its proper divisors (22751).

123100561 is an equidigital number, since it uses as much as digits as its factorization.

123100561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22750.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 123100561 is about 11095.0692201536. The cubic root of 123100561 is about 497.4544772872.

Adding to 123100561 its reverse (165001321), we get a palindrome (288101882).

The spelling of 123100561 in words is "one hundred twenty-three million, one hundred thousand, five hundred sixty-one".