123513521 has 2 divisors, whose sum is σ = 123513522. Its totient is φ = 123513520.

The previous prime is 123513499. The next prime is 123513541. The reversal of 123513521 is 125315321.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122965921 + 547600 = 11089^2 + 740^2 .

It is a cyclic number.

It is not a de Polignac number, because 123513521 - 2⁶ = 123513457 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_7030247 and since 123513521 and 7030247 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (123513541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61756760 + 61756761.

It is an arithmetic number, because the mean of its divisors is an integer number (61756761).

Almost surely, 2^123513521 is an apocalyptic number.

It is an amenable number.

123513521 is a deficient number, since it is larger than the sum of its proper divisors (1).

123513521 is an equidigital number, since it uses as much as digits as its factorization.

123513521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 900, while the sum is 23.

The square root of 123513521 is about 11113.6637073469. The cubic root of 123513521 is about 498.0101192548.

Adding to 123513521 its reverse (125315321), we get a palindrome (248828842).

The spelling of 123513521 in words is "one hundred twenty-three million, five hundred thirteen thousand, five hundred twenty-one".