123505513 has 4 divisors (see below), whose sum is σ = 123531588. Its totient is φ = 123479440.

The previous prime is 123505477. The next prime is 123505517. The reversal of 123505513 is 315505321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 315505321 = 31 ⋅10177591.

It can be written as a sum of positive squares in 2 ways, for example, as 11209104 + 112296409 = 3348^2 + 10597^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123505513 is a prime.

It is a super-2 number, since 2×123505513² = 30507223482786338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123505517) 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, 3706 + ... + 16147.

It is an arithmetic number, because the mean of its divisors is an integer number (30882897).

Almost surely, 2^123505513 is an apocalyptic number.

It is an amenable number.

123505513 is a deficient number, since it is larger than the sum of its proper divisors (26075).

123505513 is an equidigital number, since it uses as much as digits as its factorization.

123505513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26074.

The product of its (nonzero) digits is 2250, while the sum is 25.

The square root of 123505513 is about 11113.3034242749. The cubic root of 123505513 is about 497.9993561923. Note that the first 3 decimals are identical.

The spelling of 123505513 in words is "one hundred twenty-three million, five hundred five thousand, five hundred thirteen".