123521521 has 4 divisors (see below), whose sum is σ = 123688512. Its totient is φ = 123354532.

The previous prime is 123521509. The next prime is 123521533. The reversal of 123521521 is 125125321.

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.

It is an interprime number because it is at equal distance from previous prime (123521509) and next prime (123521533).

It is a cyclic number.

It is not a de Polignac number, because 123521521 - 2¹⁵ = 123488753 is a prime.

It is a super-3 number, since 3×123521521³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 123521492 and 123521501.

It is not an unprimeable number, because it can be changed into a prime (123521501) 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, 82381 + ... + 83866.

It is an arithmetic number, because the mean of its divisors is an integer number (30922128).

Almost surely, 2^123521521 is an apocalyptic number.

It is an amenable number.

123521521 is a deficient number, since it is larger than the sum of its proper divisors (166991).

123521521 is an equidigital number, since it uses as much as digits as its factorization.

123521521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166990.

The product of its digits is 600, while the sum is 22.

The square root of 123521521 is about 11114.0236188340. The cubic root of 123521521 is about 498.0208711005.

Adding to 123521521 its reverse (125125321), we get a palindrome (248646842).

The spelling of 123521521 in words is "one hundred twenty-three million, five hundred twenty-one thousand, five hundred twenty-one".