123135521 has 2 divisors, whose sum is σ = 123135522. Its totient is φ = 123135520.

The previous prime is 123135499. The next prime is 123135527. The reversal of 123135521 is 125531321.

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., 114725521 + 8410000 = 10711^2 + 2900^2 .

It is an emirp because it is prime and its reverse (125531321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 123135521 - 2⁶ = 123135457 is a prime.

It is not a weakly prime, because it can be changed into another prime (123135527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61567760 + 61567761.

It is an arithmetic number, because the mean of its divisors is an integer number (61567761).

Almost surely, 2^123135521 is an apocalyptic number.

It is an amenable number.

123135521 is a deficient number, since it is larger than the sum of its proper divisors (1).

123135521 is an equidigital number, since it uses as much as digits as its factorization.

123135521 is an evil number, because the sum of its binary digits is even.

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

The square root of 123135521 is about 11096.6445829359. The cubic root of 123135521 is about 497.5015644337.

Adding to 123135521 its reverse (125531321), we get a palindrome (248666842).

The spelling of 123135521 in words is "one hundred twenty-three million, one hundred thirty-five thousand, five hundred twenty-one".