135021 has 4 divisors (see below), whose sum is σ = 180032. Its totient is φ = 90012.

The previous prime is 135019. The next prime is 135029. The reversal of 135021 is 120531.

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: 120531 = 3 ⋅40177.

It is not a de Polignac number, because 135021 - 2¹ = 135019 is a prime.

It is a D-number.

It is a Duffinian number.

135021 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 134988 and 135006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135029) 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, 22501 + ... + 22506.

It is an arithmetic number, because the mean of its divisors is an integer number (45008).

2¹³⁵⁰²¹ is an apocalyptic number.

It is an amenable number.

135021 is a deficient number, since it is larger than the sum of its proper divisors (45011).

135021 is an equidigital number, since it uses as much as digits as its factorization.

135021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45010.

The product of its (nonzero) digits is 30, while the sum is 12.

The square root of 135021 is about 367.4520376866. The cubic root of 135021 is about 51.3019382250.

Adding to 135021 its reverse (120531), we get a palindrome (255552).

The spelling of 135021 in words is "one hundred thirty-five thousand, twenty-one".