123500021 has 4 divisors (see below), whose sum is σ = 123728844. Its totient is φ = 123271200.

The previous prime is 123500011. The next prime is 123500059. The reversal of 123500021 is 120005321.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 40780996 + 82719025 = 6386^2 + 9095^2 .

It is a cyclic number.

It is not a de Polignac number, because 123500021 - 2¹⁰ = 123498997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 123499969 and 123500005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123500011) 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, 113600 + ... + 114681.

It is an arithmetic number, because the mean of its divisors is an integer number (30932211).

Almost surely, 2^123500021 is an apocalyptic number.

It is an amenable number.

123500021 is a deficient number, since it is larger than the sum of its proper divisors (228823).

123500021 is an equidigital number, since it uses as much as digits as its factorization.

123500021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228822.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 123500021 is about 11113.0563302811. The cubic root of 123500021 is about 497.9919744625.

Adding to 123500021 its reverse (120005321), we get a palindrome (243505342).

The spelling of 123500021 in words is "one hundred twenty-three million, five hundred thousand, twenty-one".