135523021 has 4 divisors (see below), whose sum is σ = 135564544. Its totient is φ = 135481500.

The previous prime is 135523019. The next prime is 135523051. The reversal of 135523021 is 120325531.

135523021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 120325531 = 229 ⋅525439.

It is a cyclic number.

It is not a de Polignac number, because 135523021 - 2¹ = 135523019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 135522983 and 135523001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135523051) 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, 15405 + ... + 22546.

It is an arithmetic number, because the mean of its divisors is an integer number (33891136).

Almost surely, 2^135523021 is an apocalyptic number.

It is an amenable number.

135523021 is a deficient number, since it is larger than the sum of its proper divisors (41523).

135523021 is an equidigital number, since it uses as much as digits as its factorization.

135523021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41522.

The product of its (nonzero) digits is 900, while the sum is 22.

The square root of 135523021 is about 11641.4355214467. The cubic root of 135523021 is about 513.6544142492.

Adding to 135523021 its reverse (120325531), we get a palindrome (255848552).

The spelling of 135523021 in words is "one hundred thirty-five million, five hundred twenty-three thousand, twenty-one".