133523561 has 4 divisors (see below), whose sum is σ = 133906500. Its totient is φ = 133140624.

The previous prime is 133523531. The next prime is 133523567. The reversal of 133523561 is 165325331.

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 71995225 + 61528336 = 8485^2 + 7844^2 .

It is a cyclic number.

It is not a de Polignac number, because 133523561 - 2¹⁴ = 133507177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133523567) 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, 190946 + ... + 191643.

It is an arithmetic number, because the mean of its divisors is an integer number (33476625).

Almost surely, 2^133523561 is an apocalyptic number.

It is an amenable number.

133523561 is a deficient number, since it is larger than the sum of its proper divisors (382939).

133523561 is an equidigital number, since it uses as much as digits as its factorization.

133523561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382938.

The product of its digits is 8100, while the sum is 29.

The square root of 133523561 is about 11555.2395474953. The cubic root of 133523561 is about 511.1157949039.

Adding to 133523561 its reverse (165325331), we get a palindrome (298848892).

The spelling of 133523561 in words is "one hundred thirty-three million, five hundred twenty-three thousand, five hundred sixty-one".