135321521 has 2 divisors, whose sum is σ = 135321522. Its totient is φ = 135321520.

The previous prime is 135321463. The next prime is 135321523. The reversal of 135321521 is 125123531.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69889600 + 65431921 = 8360^2 + 8089^2 .

It is a cyclic number.

It is not a de Polignac number, because 135321521 - 2²⁶ = 68212657 is a prime.

Together with 135321523, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (135321523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67660760 + 67660761.

It is an arithmetic number, because the mean of its divisors is an integer number (67660761).

Almost surely, 2^135321521 is an apocalyptic number.

It is an amenable number.

135321521 is a deficient number, since it is larger than the sum of its proper divisors (1).

135321521 is an equidigital number, since it uses as much as digits as its factorization.

135321521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 900, while the sum is 23.

The square root of 135321521 is about 11632.7778711708. Note that the first 3 decimals coincide. The cubic root of 135321521 is about 513.3997153243.

The spelling of 135321521 in words is "one hundred thirty-five million, three hundred twenty-one thousand, five hundred twenty-one".