135213121 has 8 divisors (see below), whose sum is σ = 146659464. Its totient is φ = 124154880.

The previous prime is 135213107. The next prime is 135213173. The reversal of 135213121 is 121312531.

It can be written as a sum of positive squares in 4 ways, for example, as 20830096 + 114383025 = 4564^2 + 10695^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 135213121 - 2¹¹ = 135211073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135213521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96300 + ... + 97693.

It is an arithmetic number, because the mean of its divisors is an integer number (18332433).

Almost surely, 2^135213121 is an apocalyptic number.

It is an amenable number.

135213121 is a deficient number, since it is larger than the sum of its proper divisors (11446343).

135213121 is a wasteful number, since it uses less digits than its factorization.

135213121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194051.

The product of its digits is 180, while the sum is 19.

The square root of 135213121 is about 11628.1176894629. The cubic root of 135213121 is about 513.2625915428.

Adding to 135213121 its reverse (121312531), we get a palindrome (256525652).

The spelling of 135213121 in words is "one hundred thirty-five million, two hundred thirteen thousand, one hundred twenty-one".